The aim of the current study was to examine how decisions are made and who is involved in decision-making regarding provision of adjustments for students with special educational needs in Australian mainstream schools. A total of 107 stakeholders were interviewed across 22 schools. Participation in decision-making varied, with students the least likely to be involved. There was variation in the degree and nature of collaboration and the degree to which decisions were subject to review. The focus of decision-making processes also varied, with some schools focusing on funding and resource allocation and others on broader support considerations. Schools used a range of formal and informal levels of decision-making but the degree to which they agreed on factors that underpinned decisions (values, legal considerations, etc.) was variable and sometimes limited. Possible explanations for the observed patterns of decision-making are offered, practical implications considered and directions for future research outlined.