Maria Montessori’s Educational Approach to Intellectual Disability and Autism: A Systematic Review of Quantitative Research

Abstract

The Montessori method was originally developed from an examination of children with cognitive disabilities. Numerous studies have explored the application of Montessori principles with typically developing children and adolescents across different educational settings. However, despite its original interest in children with cognitive disabilities, there has been a limited number of systematic reviews specifically addressing its impact on these children. We conducted a systematic review of quantitative research based on a search of the literature on the effects of the Montessori educational approach in teaching academic and non-academic skills to children and young people with intellectual disabilities (IDs) and autism. A search was conducted of seven bibliographic databases: Embase, PubMed/MEDLINE, PsycINFO, Cochrane Library, Ebscohost, Proquest, and Scopus, until 31 October 2024. We identified 7165 reports, 3 of which meet the inclusion criteria for the review. The selected studies reported improvements in the areas investigated, including motor skills, perceptual abilities, cognitive development, and self-care, confirming the effectiveness of the Montessori methodology. Although there are few experimental studies available, these findings provide valuable operational insights. They suggest that we can return to the roots of the method, which was originally designed for children with mental disorders. An experimental approach to this time-honored method could enhance its application in neurodevelopmental disorders, maximizing autonomy and inclusion while improving the quality of life for individuals with disabilities.

1. Introduction

Building on the work of Édouard Séguin, Maria Montessori embraced the challenge of developing a new educational approach for children with intellectual disabilities, who historically were referred to as intellectually “deficient” or “frenasthenic”, a term coined around the end of the 19th century to refer to those who were unable to rise above the infantile stage (i.e., “imbeciles”, “cretins”, “idiots”; Babini, 1996). Her guiding principles stemmed from a key insight: that the issues surrounding these children should be viewed more through a pedagogical lens than a medical one (Bollea, 1998).

The debate in psychiatry regarding the causes and classification of mental disorders began in the late 17th century and early 18th century, focusing on how to treat or prevent these conditions (Petretto et al., 2025). Since ancient times and subsequently throughout the centuries, many scholars have attempted to classify mental disorders mainly, if not exclusively, from a medical standpoint (Mack et al., 1994). Within this context, Maria Montessori’s educational approach for children with frenasthenia emerged as part of the broader scientific and pedagogical discussions of the time. This debate aimed to define and classify “frenasthenia” while seeking appropriate educational methods for addressing the mental and behavioral disorders characteristic of this population. Since they were locked up in mental hospitals run by staff who were often unprepared to care for their disability, children with frenasthenia experienced their illness as a source of social isolation, which contributed to accentuating their cognitive delay. In these terms, mental illness manifested itself as a disorganization of inner development, which, as such, affected the child’s behavior, causing indisputable signs of moral disorder and psychic deviation (De Serio, 2013).

Montessori, based on her studies and observations, proposed a classification of children with frenasthenia into three categories: very severe, severe, and late-onset. She also outlined tailored educational pathways for each group (Montessori, 1902). For Montessori, medicine and education served as the foundations for caring for individuals with cognitive disabilities (Montessori, 1970). In her educational philosophy, the role of teachers and their training are vital for successfully implementing educational activities. Montessori believed that teachers should engage with children on their level to foster knowledge and understanding of the world, serving as activators of the child’s “dormant soul”. Specifically, teachers working with children with mental disabilities need specialized training to understand their students’ characteristics and the unique educational methods required (Molineri & Alesio, 1899).

Structured materials facilitate interactions between children and materials that guide their exploration and learning. This structured approach removes randomness and focuses on acquiring specific skills. Key characteristics of structured materials include (a) stimulating the child regarding specific aspects of the intended activity; (b) encouraging the child to concentrate on one concept at a time; (c) allowing for abstraction through manipulation; d) controlling and guiding the child’s activity by enabling self-correction of errors (Tornar, 1982). For example, sensory learning, as described by Montessori, acts as a cognitive organizer. It uses everyday materials from the curriculum to guide the development of cognitive functions. Therefore, structured materials serve as a foundation for actual learning in various school subjects. It is then the responsibility of the school to provide appropriate tools that facilitate and promote the self-constructive processes of knowledge (Montessori, 1970).

The self-directed exercise and error control that a child engages in by directly interacting with objects in their environment leads to the gradual transformation of knowledge. Initially, this knowledge is absorbed in a confused and unconscious manner, but, through sensory experiences and movement, it becomes organized and conscious (Gallelli, 2008). Therefore, the child’s ability to focus on various activities, which they can choose based on their interests and carried out in a preferred space (e.g., a mat), is crucial. These activities typically occur during a “work cycle” lasting about three hours, guided by the teacher. The teacher’s interventions during this time should be minimal and follow a predetermined approach. The teachers must establish clear objectives for their interventions based on careful observation and understanding of the child (Tornar, 1982).

Her direct experience with children with frenasthenia allows her to highlight both qualitative and quantitative differences compared to typically developing children. For instance, she observes differences in their ability to concentrate on spontaneous exercises and in their responses of interest, curiosity, and exploration of objects. Montessori, in developing her experimental research, asserts that “intellectually disabled” children, due to their unique cognitive and behavioral characteristics, need engaging objects to view and manipulate to stimulate their curiosity, attention, desire, and interest. Therefore, she recommends short, repeated lessons, following Séguin’s three-step lesson plan (association, recognition, memory), structured in the form of games to arouse the child’s interest and with reinforcement to motivate them to work (Montessori, 1916).

The insights obtained during her years of educational practice with children who had learning challenges led her to believe that the principles of the activities and materials she developed should be applied to all children, particularly those under six years old. She recognized that every child could benefit from these resources at their own level. As a result, her educational approach is inclusive, valuing each child’s unique academic journey. It emphasizes the importance of acknowledging different learning paces and the skills to be nurtured, thereby promoting individualized teaching that respects each child’s individuality (Caprara & Macchia, 2019).

The Montessori method emphasizes the cognitive, adaptive, and social development of children. It has been adopted by various educational practices worldwide, including many schools and institutions. Numerous studies have explored the application of Montessori principles with typically developing children and adolescents in different settings (e.g., private, public, and special schools), covering a range of ages and teaching objectives—both academic and non-academic. Several reviews have provided significant evidence regarding the effectiveness of the Montessori method compared to other educational approaches. It has been shown to support visual perception (Kıran et al., 2021) and motor development in younger children (Marshall, 2017), facilitate the learning of school skills (Marshall, 2017; Lillard, 2012, 2016; Lillard & Else-Quest, 2006; Ackerman, 2019; Demangeon et al., 2023; Randolph et al., 2023), and enhance the development of executive functions (Randolph et al., 2023). While there is some evidence of positive effects on social skills and creativity (Demangeon et al., 2023; Randolph et al., 2023), these findings are less robust.

Purpose of This Review

It is important to note that many existing reviews primarily focus on the general population of children. In contrast, the Montessori method originated from the study of children with cognitive disabilities. To the best of our knowledge, there are no recent reviews of the literature that specifically address the effects of the Montessori method on children and young people with disabilities and autism, except for a conceptual paper focusing on the role of play-based learning activities using the Montessori approach (Marks, 2016). This raises an important question: is there any research published on the benefits of the Montessori method for children and young people with intellectual disability (ID) and autism? Intellectual disability is characterized by considerable limitations in intellectual functioning and adaptive behavior, including conceptual, social, and practical skills (Schalock et al., 2021). Autism falls under a broader category of neurodevelopmental disorders, which are marked by early-onset challenges in motor skills, language, learning, adaptation, and social communication (Tafolla et al., 2025). Given that the Montessori method aims to support cognitive, adaptive, and social development, it may effectively meet the educational and adaptive needs of children and young people with ID and autism. This systematic review focuses on quantitative research investigating whether the Montessori educational approach has proven effective in teaching academic and/or non-academic skills to children and young people with ID and autism.

2. Materials and Methods

2.1. Study Design and Search Strategy

Following the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines, we reviewed studies published up to 31 October 2024. We conducted the search with no limits on the date of publication, no geographic limitation, no age range limitation, in peer-reviewed journals, and in the English language. We examined the published literature using online databases that cover the education and psychology areas. We examined the following databases: Embase, PubMed/MEDLINE, PsycINFO, Cochrane Library, Ebscohost, Proquest, and Scopus. We used the following term combination: (“Montessori”) AND (“intellectual disability” OR “developmental disabilities” OR “mental retardation” OR “special education” OR “special needs” OR neurodevelopmental disorders” OR “autism”).

2.2. Selection Criteria

We included studies that (a) reported original research, (b) included groups with ID or autism spectrum disorder, (c) used experimental groups with random assignment, (d) examined the effectiveness of the use of Montessori method with structured materials (either basic and/or those more specific to different school subjects), (d) included a control group. We excluded studies that (a) used single-participant or case studies, (b) did not include a control group, (c) used qualitative design, (d) used quasi-experimental design, (e) used only Montessorian materials without explicit use of intervention based on the Montessori method, or (f) appeared in reviews, theoretical articles, comments, conference abstracts, conference proceedings, and editorials or letters.

In this systematic review of the literature, we chose to analyze the results of quantitative research because it offers several advantages, including the possibility of generalizing the results to a wider population, objectivity thanks to the use of standardized measurements, the replicability of results, and statistical analysis that allows for the identification of cause-and-effect correlations.

2.3. Selection Procedures, Screening and Data Elaboration

Figure 1 shows the selection process of the studies. Two authors (F.D.D. and S.B.) conducted the search and selection of papers, while three other authors (A.A.C., G.L., and M.A.S.) determined their eligibility. In the initial identification phase, the research algorithm produced a total of 7165 records. We implemented various screening steps to assess the suitability of these articles based on our inclusion and exclusion criteria. First, we excluded 3949 duplicates. After this, we screened the remaining 3216 records to identify articles that fit our study parameters. Based on the titles, we eliminated 3205 records that consisted of reviews, theoretical articles, comments, conference abstracts, conference proceedings, editorials, letters to the editor, or studies focused on biological or medical topics (e.g., neurodegenerative diseases or genetic syndromes). Next, we examined the abstracts, and, in some cases where critical information was missing, we retrieved the full texts to determine if the articles adhered to the inclusion criteria. In cases where two judges did not consider papers aligned with the inclusion criteria, they discussed discrepancies until a consensus was reached. If an agreement could not be achieved, a third author made the final decision.

As a result of this screening process, 11 papers were deemed eligible for full reading (with thorough checking of all inclusion criteria) and possible consideration for the present review. From these, we excluded eight manuscripts that did not fully meet the inclusion criteria. Specifically, one was a case report (Winarni et al., 2012), one was a case study (Iwanowski et al., 2005), and five used only Montessori materials without an intervention based on Montessori’s approach (Ho et al., 2018; Liggett et al., 2018; Kimball et al., 2020; Shvarts et al., 2020; Keevy et al., 2022); finally, the study by Sarimski (1999) lacked a control group (for details on these studies, see

Table 1. Excluded items with justification.

References	N	Chronological Age M (S.D.) Years	Intervention Characteristics/Materials/Study Design	Reason for Exclusion
(Ho et al., 2018)	N = 5 children, 3 boys, 2 girls with ASD	Range 3–8 years	Montessori object permanence boxes	Only use of materials without intervention with Montessori method
(Liggett et al., 2018)	N = 3 children, 2 boys, 1 girl with ASD	Range 2–8 years	Montessori object permanence box	Only use of materials without intervention with Montessori method
(Kimball et al., 2020)	N = 10 children with ASD, 1 language delay, 1 neurotypical	Range 2–8 years	Montessori object permanence boxes	Only use of materials without intervention with Montessori method
(Shvarts et al., 2020)	N = 5 children with ASD	Range 2–8 years	Montessori object permanence boxes	Only use of materials without intervention with Montessori method
(Keevy et al., 2022)	N = 3 children with ASD	Range 6–8 years	Montessori object permanence boxes	Only use of materials without intervention with Montessori method
(Sarimski, 1999)	N = 10 children, 5 boys and 5 girls, Williams syndrome	Range 1–6 years	Play sessions following the Montessori approach	Missing control group
(Winarni et al., 2012)	N = 1 boy and 1 girl fragile-X syndrome	Range 3–7 years	Program with elements of Montessori homeschooling	Case studies
(Iwanowski et al., 2005)	N = 1 boy with Wolf–Hirschhorn syndrome	1–10/12-year-old	Interactive play sessions according to Montessori principles	Case study

). Ultimately, a total of three studies met the inclusion criteria, which required original research, groups with intellectual disabilities or autism spectrum disorder, experimental groups with random assignment, the use of the Montessori method with structured materials, and the presence of a control group. We included these three studies in the present systematic review.

3. Data Synthesis

Considering the limited number of studies included, we aimed to make a synthesis that included the description, organization, exploitation, and interpretation of the studies, considering their methodological adequacy. Details about the methodology and results of the single studies are presented in

Table 2. List of selected studies.

References	N	Chronological Age M (S.D.) Years	Country	Context	IQ	Intervention Characteristics	Outcome Measures	Study Design	Findings
(M. Kaya & Yildiz, 2019)	N = 24 men with ID (N = 12 control group, N = 12 experimental group)	Range 20–22 years	Turkey	Private School	-	Sensorial materials; daily life materials; mothers’ support intervention (8 week formation)	Movement test (standing broad jump tests; medicine ball throw test; flexibility measurement; handgrip strength measurement; 20 m sprint test; standing stork test—blind); perception test (evaluating visual perception skills)	Random cluster sampling method	Improvement in visual perception skills, except the shape–ground connection, and in movement skills
(E. Ö. Kaya & Torun, 2022)	N = 20 boys with ID (N = 10 control group, 5 Down syndrome, 5 ASD; N = 10 experimental group, 5 Down syndrome, 5 ASD)	Range 12–16 years	Turkey	Special education and rehabilitation centers	-	Montessori education materials	Eurofit test batteries (height and body weight measurements; flamingo balance test; plate tapping test; sit and reach test; standing long jump test; handgrip test)	Random cluster sampling method	Improvement in physical activities and some motor skills according to the results of plate tapping, standing long jump, and sit and reach tests
(Afshan et al., 2024)	N = 30 (43.3%) girls with ID (N = 15 control group, N = 15 experimental group)	M = 10.01 (2.84) Range 6–13 years	Pakistan	Special education school	50–70	Sensorial materials; 2 sessions (each session 50–60 min); 1 expert, and 3 special teachers	Cognitive Abilities Checklist; Adaptive Function Assessment Form	Randomized control trial	Improvement in cognitive abilities, communication, and self-care domain

.

4. Results

We found three studies on the effectiveness of the Montessori method with children and youth with ID.

The purpose of the study by M. Kaya and Yildiz (2019) was to evaluate the effectiveness of the Montessori program on the motor and visual perception skills of a group of students with mild ID. Twenty-four male students between the ages of 20 and 22 participated in the study, which was conducted in a private school in Turkey. The experimental group, selected according to the random cluster sampling method, consisted of 12 participants who had received education according to the Montessori method; the control group included the other 12 students who had not received Montessori educational interventions. The experimental group followed a Montessori educational program for 8 weeks; the course was joined voluntarily by the students’ mothers, who were specially trained to support the activities to be carried out in the home environment. The educational program included the use of materials for daily practical life exercises and the use of materials for sensory development. In contrast, the control group had a routine educational program for 8 weeks. The measures used to test the effectiveness of the Montessori method were as follows: (a) regarding motor skills: standing broad jump test; medicine ball throw test (MBT); flexibility measurement; handgrip strength measurement; 20 m sprint test; standing stork test—blind; (b) regarding perceptual skills: evaluating visual perception skill. The experimental design included pretest and post-test measurements to test the treatment effect. The results obtained showed that there were no significant differences in motor and perceptual performance between the experimental group and the control group. The pretest and post-test values in individuals with ID were significantly different in all the measures used except for the left foot balance test. In the control group, all pretest and post-test values concerning measures of motor skills showed a significant difference. Relative to perceptual skills, there were no significant differences in the measures used for individuals with ID or in the control group, except for the figure-background subtest. The authors concluded that the effect of the Montessori program on the motor and perceptual skills of individuals with MID provided similar values to classical education. Therefore, they propose that the Montessori method can also be used as an alternative to the classical educational method for people with ID.

The study by E. Ö. Kaya and Torun (2022) investigated the effects of the Montessori educational method on children with Down syndrome and autism. The researchers aimed to compare the outcomes of children who received Montessori education with those who did not using the Eurofit test batteries to assess their motor and fitness skills. The study included twenty boys, aged between 12 and 16, with an equal representation of ten boys with Down syndrome and ten boys with autism. The treatment group, which received Montessori education, consisted of five boys with Down syndrome and five with autism; by contrast, the control group, also comprising five boys with each condition, received traditional education. The Eurofit test batteries included various subtests, i.e., height and body weight measurements, the flamingo balance test, the plate tapping test, the sit and reach test, the standing long jump test, and the handgrip test. The experimental design included pre- and post-test measurements to evaluate the impact of the educational method. When examining performance differences between the pre- and post-test results, significant improvements were observed in the treatment group for the plate tapping and the standing long jump tests. In contrast, the control group showed a significant improvement only in the sit and reach test. A statistically significant difference was found between the pretest and post-test measurements of the treatment and control groups in the plate tapping and the standing long jump tests. However, no significant differences emerged in the flamingo balance test, handgrip test, or sit and reach test. The authors conclude that using Montessori educational materials can enhance the motor skills of children with disabilities. Overall, children with Down syndrome and autism who participated in activities based on the Montessori method demonstrated significant improvements in specific physical and motor skills, particularly in manual speed and explosive muscle power. These findings support the effectiveness of Montessori activities, as some subtests displayed substantial improvements. Furthermore, the lack of differences in performance on other subtests suggests that both Montessori and traditional education methods yield equivalent results. The authors recommend that educational programs for children and adolescents with disabilities, including autism, integrate Montessori activities alongside traditional teaching methods.

The study by Afshan et al. (2024) aimed to evaluate whether the cognitive abilities and adaptive functioning of 30 children (43.3% girls) with mild intellectual disabilities could be improved through a Montessori sensory training program. The children were randomly assigned to either an experimental group, which received the Montessori method, or a control group. The sensory training focused on three areas of intervention: the visual–chromatic area, the auditory area, and the tactile–thermal, baric, and stereognostic areas. The intervention comprised two sessions, each lasting 50 to 60 min. The first session involved the presentation of Montessori materials, while the second session allowed the children to use these materials independently. An operator trained in the Montessori method supervised the sessions with the assistance of three special education teachers trained to conduct the training. To assess improvements in cognitive abilities, teachers completed a questionnaire developed from Piaget’s theory of cognitive development, which consisted of six subscales: classification, seriation, shape recognition, color and number recognition, sorting, and visual/auditory discrimination. Adaptive functioning was measured using the Adaptive Function Assessment Form scale, which included two subscales (communication and self-care) and was also completed by the teachers. The research design included pretests and post-tests to evaluate the effectiveness of the treatment. The experimental group demonstrated significant improvements in cognitive ability, communication, and self-care compared to the control group. Despite some limitations in the study (e.g., using a limited number of evaluation instruments), the findings suggest that Montessori sensory training is a promising intervention to encourage independent learning in children with mild intellectual disabilities.

Summary of Studies

The three selected studies focus on children and young people with intellectual disabilities and autism. However, there are several key differences among them. First, the age range of participants varies significantly. Afshan et al. (2024) included participants aged 6 to 13 years, while M. Kaya and Yildiz (2019) studied individuals aged 20 to 22 years. Second, the gender distribution among participants is uneven. The studies conducted by M. Kaya and Yildiz (2019) and E. Ö. Kaya and Torun (2022) included no female participants, whereas Afshan et al. (2024) had a balanced sample with about half of the participants being girls. Third, the studies were conducted in different contexts: M. Kaya and Yildiz (2019) took place in a private school, E. Ö. Kaya and Torun (2022) occurred at special education and rehabilitation centers, and Afshan et al. (2024) in a special education school. Fourth, two studies (M. Kaya & Yildiz, 2019; E. Ö. Kaya & Torun, 2022) aimed to evaluate the impact of the Montessori method on motor skills, while Afshan et al. (2024) focused on cognitive and adaptive skills. The studies by M. Kaya and Yildiz (2019) and Afshan et al. (2024) specified the use of Montessori sensory materials, while E. Ö. Kaya and Torun (2022) did not mention the type of materials used. Fifth, the duration of the interventions varied. The treatments in the studies by M. Kaya and Yildiz (2019) and Afshan et al. (2024) lasted between two and four months, while the duration in E. Ö. Kaya and Torun (2022) was approximately one year. Finally, E. Ö. Kaya and Torun (2022) and Afshan et al. (2024) provided details on the training characteristics of the operators or teachers conducting the interventions, while M. Kaya and Yildiz (2019) involved the mothers of the young participants in the treatment. By contrast, all studies shared an experimental design and were conducted on the same continent (Asia).

5. Discussion

Montessori’s educational principles and structured materials have been applied in many areas of the world and in the education of typically developing children and adolescents (Marshall, 2017; Lillard, 2012, 2016; Lillard & Else-Quest, 2006; Ackerman, 2019; Demangeon et al., 2023; Denervaud et al., 2019; Randolph et al., 2023), children with learning disabilities (Pickering, 1992), and adults with neurodegenerative diseases (Sheppard et al., 2016).

This systematic review aimed to examine the quantitative research on the use of the Montessori methodology in teaching children and young people with ID and autism. The three selected studies included children and young people with intellectual disabilities and autism. The participants differed in terms of chronological age, type of setting, objectives, materials, and treatment characteristics. The sample sizes were small, and the females were underrepresented. The experimental design of the studies was appropriate for the intended purpose. No study reported what type of training the teachers received to design and implement the learning path for the members of the experimental group. Only one study (M. Kaya & Yildiz, 2019), which also included the mothers of the young people involved in the treatment, reported the hours and topics of their training. Finally, the fact that there are only a limited number of schools and that they are all located on the same continent suggests that the structure of a country’s education system may limit opportunities for Montessori schools to develop. This is the case in many countries, where the implementation of a true Montessori approach is prevented by the fact that most preschool education is provided by kindergartens, whose teaching principles are similar to those of the Montessori method (Demangeon et al., 2023).

The three studies report improvements in the areas investigated (motor, perceptual, cognitive, and self-care), confirm the effectiveness of the Montessori methodology, and propose its use as an alternative to traditional educational methods. However, the results obtained, which require further evidence, the limitations of the literature search methodology (use of selected databases, exclusion of grey literature, stringent search criteria), and cultural and school system aspects that may slow the spread of the Montessori method in schools call for caution in generalizing conclusions about the effectiveness of the Montessori method among children with cognitive disabilities.

While experimental studies on the Montessori method are limited, they offer valuable insights and demonstrate that research can return to its historical roots: focusing on children with mental disorders. In this vein, the goal of adopting an experimental approach is not so much to validate this educational practice, which has been known and applied for over a century with mixed results (Lillard et al., 2025), but to enhance its application for the specific educational needs of children with neurodevelopmental disorders. For instance, in the context of educational interventions for children and young people with autism, some evidence-based practices share fundamental educational principles with Montessori, e.g., modeling, visual support, peer-mediated instruction, and social narratives (Epstein et al., 2020). Additionally, Montessori motor activities have been recognized as beneficial for improving executive functions (Diamond & Lee, 2011), and they could be integrated into motor programs designed for the rehabilitation of children with autism spectrum disorder (Liang et al., 2022). Several studies have also adopted materials inspired by the tools used in Montessori education (Ho et al., 2018; Liggett et al., 2018; Kimball et al., 2020; Shvarts et al., 2020; Keevy et al., 2022). However, the Montessori method’s theoretically sound foundations and its potentially effective practical applications necessitate equally robust empirical evidence to support them (Li, 2025).

In recent years, studies have emerged that focus on the intersection of neuroscience and educational processes (L’Ecuyer et al., 2020) as well as neural correlates (Wu et al., 2021). Many of these studies, especially those examining the effects of the Montessori method, reveal differences in learning strategies and creative processes between students in Montessori schools and those in traditional educational settings (Denervaud et al., 2020; Duval et al., 2023; Zanchi et al., 2024). Implementing the Montessori educational system could provide valuable insights into the impact of the educational context on children’s development. Furthermore, it may help identify more personalized treatment objectives and methods aimed at enhancing their autonomy, inclusion, and quality of life.

Montessori’s educational approach shares some fundamental principles with Universal Design for Learning (Rose & Gravel, 2010) as both respond to the needs of all children, specifically respecting the unique characteristics, learning styles, and potential of each child with and without disabilities as well as ensuring inclusion and accessibility in educational settings for all (Rosati, 2021). The accessible environment, structured materials, promotion of autonomy, multi-age classrooms that offer natural peer-tutoring support, knowledge building, and individualization of the learning experience (Sablić et al., 2025) make the Montessori approach a possible response to the challenge posed by inclusive, complex, and multifaceted education for people with disabilities, especially children with autism, given their behavioral characteristics in social, emotional, and cognitive development (Tīģere et al., 2025).

6. Implications for Clinical Practice and Research

Rehabilitation treatment for children with intellectual disabilities (IDs) and autism is not limited to a single type of intervention (e.g., physiotherapy or speech therapy). Instead, treatment often involves a combination of interventions tailored to the child’s specific needs. Therefore, Montessori activities, or aspects of them, can be integrated into the rehabilitation plan depending on the child’s neuropsychological and sensory profile. In rehabilitation practice, as various studies have shown, interactive technology can also be beneficial for children with intellectual disabilities (dos Santos Nunes et al., 2017). While more evidence is still needed, this type of technology engages both cognitive and motor functions, providing valuable information for assessing and treating these areas. Additionally, the Montessori method incorporates the use of “mechanical” tools, i.e., basic programming and computing with concrete manipulatives (e.g., physical coding blocks) and tangible interfaces (e.g., robots) (Venturi, 2023). Today, we can assert that technological tools (e.g., tangible user interfaces, TUIs; Zuckerman et al., 2005) can support learning abstract concepts that are often challenging for individuals with IDs. An example of a TUI tool inspired by Montessori principles (facilitated learning environment, usability, procedural order, autonomy of use) is visual spatial cubes (VICs) for memory training, composed of an hosting board, a set of nine cubes, and an app for mobile and PC, which are integrated to enable the user to perform variety of tasks stimulating memory skills. They can also enhance functions that may be lacking, such as memory (Beccaluva et al., 2022).

7. Limitations

With our systematic review, we highlight a gap in studies on the effect of the Montessori method on children and adolescents with ID and ASD. The results are based on only a few studies, preventing us from drawing firm conclusions. Thus, our review has some limitations. A first limitation is the method used for the literature search. Our research was based on established databases and excluded additional sources, i.e., grey literature (e.g., theses/dissertations, government or technical reports, evidence-based guidelines, white papers, emerging data), as they do not always ensure the reliability of results since they are not subject to thorough and qualified reviews. Among the literature search criteria, one possible additional limitation is the lack of an age range limit for participants; as a result, many records were included, and, consequently, we found many duplicate studies involving adults with neurodegenerative diseases. Among the selected studies, there are limitations in methodological quality due to small sample sizes, an unbalanced male-to-female ratio, unclear descriptions of the intervention methodology, and different outcome measures that do not allow for comparison of results. These biases might have altered the results obtained. The fact that there are only a limited number of schools and that they are all located on the same continent suggests that the structure of a country’s education system may limit opportunities for Montessori schools to develop. This is the case in many countries, where the implementation of a genuine Montessori approach is prevented by the fact that most preschool education is provided by kindergartens, whose teaching principles are similar to those of the Montessori method (Demangeon et al., 2023).

The presence of only a few studies and the limited methodological quality of those excluded during the selection process does not indicate a lack of interest in Montessori’s approach. By contrast, they highlight the ongoing effort needed to apply her method in this area, preventing us from drawing definitive conclusions. From the discussed studies, it is evident that future research should consider several variables when assessing the effectiveness of Montessori education. These variables include the characteristics of the participants (i.e., age, male/female proportion, sample size, diagnosis, and comorbidities), the type of educational setting, the methodology employed (research design), the characteristics of the treatment (i.e., the type of materials used), the training of practitioners, and the specific treatment goals (for example, cognitive skills, adaptive functioning, or academic skills) (Randolph et al., 2023).

8. Conclusions

The use of the Montessori method with children and adolescents who have intellectual disabilities and autism presents a significant challenge for researchers, teachers, and educators. Montessori’s educational approach, which begins with a well-organized environment and incorporates appropriate stimuli, techniques, procedures, and materials, has specific goals and objectives. Albeit limited, the reviewed evidence indicates that this method could create favorable conditions that empower and enhance the individual abilities of children and youth with intellectual disabilities and autism.