Background: High friendship quality is often defined by high levels of intimacy, companionship, closeness and low levels of conflict. Quality friendships develop over time and may be influenced by both behaviour problems and social skills. Materials and methods: Participants were 103, 13-year-old adolescents with or without intellectual disabilities in the United States. Adolescents and their mothers participated in an open-ended interview of friendship quality and completed measures of social skills and behaviour problems. This study addressed differences in friendship quality between children with and without intellectual disabilities and explored early indicators of friendship development. Results: Adolescents with intellectual disabilities (ID) had friendships characterized by significantly lower levels of warmth/closeness and positive reciprocity than their typically developing peers. Likewise, adolescents with ID spent less time with friends outside of school and were less likely to have a cohesive group of friends. Social skills and behaviour problems at age 9 predicted friendship quality at age 13 above and beyond disability status, with higher levels of social skills and lower levels of behaviour problems related to higher ratings on measures of friendship quality. Conclusions: It appears that adolescents with intellectual disabilities have friendships that are characterized by less warmth/closeness and less positive reciprocity than the friendships of their typically developing peers. This discrepancy appears to be impacted by early social skills and behaviour problems in addition to the presence of the intellectual disability.