Children with special educational needs included in Austrian mainstream schools are provided with special educational support, which aim to create learning environments, that meet the children’s needs on an individual level. Little is known about what adjustments children with special educational needs in mainstream school classes require to promote participation in school occupations. This is the first study in Austria exploring the student-environment-fit from self-perceived children’s perspective and comparing this to teachers’ perspective by using the School Setting Interview. In this cross-sectional matched pairs study twenty-five children (mean age 12.5 ± 1.4) with special educational needs and twenty-one teachers from six Austrian secondary schools were interviewed. Participants’ ratings were analyzed descriptively and statistically with Wilcoxon-Sign Rank Test. Reported adjustments from the child and teacher perspectives were analyzed with qualitative content analysis and presented using the occupational, social and physical environmental dimensions from the Model of Human Occupation. Results indicate perceived student-environment-fit differs between school activities as well as between children and teachers. Three out of 16 school activities showed a statistically significant difference between children and teacher matched-pair analysis. Children perceive more unmet needs then teachers. Most adjustments are reported in the social environment dimension and inform practitioners what adjustments are perceived to be useful for children with Special Educational Needs and their teachers. Both children’s and teacher’s perspectives provide valuable information. Significantly, children in this study were able to identify required needs and describe adjustments. To increase participation in school occupations, children can and need to be actively included in the decision-making process.