Purpose: Collaboration between parents and professionals is essential to enable participation of children with disabilities. Participation is a widely researched topic in pediatric rehabilitation, and evidence for it providing opportunities for involvement and a sense of belonging in community and in larger society exists. There are, however, less research results on how collaboration builds participation pertaining to involvement in life situations. In collaboration with parents, therapists and teachers, the aim of the study was to describe factors that (a) promote and (b) prevent participation in life situations for school-aged children with disabilities, working towards participation in adulthood. Methods: The study applied a qualitative research design. The data was collected during the 2015–2016 academic year with five focus-group interviews by sampling procedure. The study involved five parents of children with disabilities, three therapists and two teachers. The research data was analyzed by inductive content analysis. Results: The results identified thirteen factors that promote child participation, with an emphasis on taking the child’s individuality into account. There were three barriers, which focused on attitudes or technical issues. Conclusions: The results suggest that collaboration on child-related factors has been well identified and implemented, but collaboration on enabling environmental factors needs to be developed. The results can be utilized to design what adults’ collaboration should focus on in promoting child participation.