Collaborative practice between teachers and occupational therapists is promoted as best-practice to support the inclusion of students with disabilities in mainstream classrooms. However, interprofessional practice across the disciplines of education and health is complicated, and success is mediated by personal, professional, and system factors. This qualitative ethnographic study used shadowing, contextual conversations, and interviews to explore collaboration between teachers (n = 11) and occupational therapists (n = 10) in mainstream primary schools (n = 10) in three Australian states to better understand how context impacts practice. Findings reveal that collaborative practice is influenced both by the model of occupational therapy service delivery employed as well as professional differences between teachers and therapists. A move from itinerant to embedded models of service delivery may support collaboration and help bridge differences between professionals through improved communication and mutual professional development.