Students with intellectual disabilities (ID) often experience difficulties in their peer relationships at school. Although a broad knowledge base on peer relationships in inclusive classrooms exists, much less is known about peer relationships in special needs classrooms. We conducted a systematic review of the literature on peer relationships in special needs classrooms for students with ID. Studies that provided information on social status, social interactions, friendships, or the classroom networks of students with ID in special needs classrooms were included. Findings from 36 studies suggest that students with ID in special needs classrooms develop and maintain differentiated peer relationships. The characteristics of these peer relationships vary depending on student (e.g., cognitive skills) and classroom factors (e.g., type of special needs classroom). Results are discussed in terms of their relevance for supporting peer relationships between students with ID. Future directions for studying peer relationships in special needs classrooms are proposed.