As school authorities strive toward inclusive models of education for children with neurodevelopmental delay and disability (NDD), many kindergarten curricula have mandated pedagogy centered on learning through play. Children with NDD tend to experience greater social isolation and lower rates of social play engagement compared to typically developing peers. Consequently, issues related to social participation and inclusion may be particularly salient in play-based kindergarten classrooms. The current qualitative study explored how eight kindergarten teachers in Ontario, Canada conceptualized and promoted inclusion in play for children with NDD. Classroom observation and teacher interviews were conducted with a focus on the teacher's role in play. Teachers endorsed the use of several indirect (i.e., environmental) strategies to promote social participation, alongside proactive teacher support in play. Teachers who shared multiple aspects of an interventionist viewpoint toward disability, and identified the social benefits of inclusion in play for children with NDD, tended to provide more proactive support to all children in play. Teachers also provided reactive support in play to address emerging social conflict. Implications for fostering the meaningful inclusion of children with NDD in play-based learning are discussed.