Autistic students face extensive challenges in social inclusion and acquisition of educational goals in comparison to their peers. Teachers’ insufficient training in alternative teaching methods and the inflexibility of educational strategies limit autistic learners’ opportunities for meaningful socio-educational inclusion (Autism Europe 2022). The current educational offer brings to no surprise the lack of disability-inclusive classroom opportunities in Environmental Education (EE) and Citizen Science (CS) co-participatory scientific research projects, for developing environmental literacy and societal collaboration in inclusive Green action. The DivEE project will utilise the potential of environmental CS as a flexible and adaptable educational method for the socio-educational inclusion of autistic learners (12–16-year-olds) in EE in secondary schools. It will develop the pedagogical resources, digital tools and teachers’ upskilling opportunities to enable the implementation of disability-inclusive classroom CS projects, via a process of co-design and co-participation. 60 secondary educators, autism professionals, CS experts and the autism community will participate in roundtables and webinars and be introduced to the value of inclusive environmental classroom CS via an e-book. The novel Autism-Inclusive CS Toolkit, complete with digital learning nuggets, interactive resources and 6 adapted CS projects, will enable stakeholder training (20) and the co-creation/adaptation of 4 national CS projects at the transnational training activity (LTCA). Teachers in 8 schools will foster the inclusive participation of 92 autistic students and their peers in CS classroom projects. 3 CS Festivals will expand participation to 90 school-community members, raising awareness and social cohesion. A Reflective Account will synthesise the socio-educational outcomes of inclusive participation in CS, opening avenues to the mainstreaming of the DivEE approach across EU schools.