Repetitive behaviors are observed in autism spectrum disorder and obsessive-compulsive disorder. Clinically, obsessive-compulsive disorder obsessions are thought to drive repetitive or ritualistic behavior designed to neutralize subjective distress, while restricted and repetitive behaviors are theorized to be reward- or sensory-driven. Both behaviors are notably heterogeneous and often assessed with parent- or clinician-report, highlighting the need for multi-informant, multi-method approaches. We evaluated the relationship between parent- and child self-reported obsessive-compulsive disorder symptoms with parent-reported and clinician-indexed restricted and repetitive behaviors among 92 youth with autism spectrum disorder (ages 7-17years). Regression analyses controlling for the social communication and interaction component of parent-reported autism spectrum disorder symptoms indicated child self-reported, but not parent-reported, symptoms of obsessive-compulsive disorder were associated with clinician-observed restricted and repetitive behaviors. Although both parent- and child self-reported obsessive-compulsive disorder symptoms were associated with parent-reported restricted and repetitive behaviors, the overlap between parent-reports of obsessive-compulsive disorder symptoms and restricted and repetitive behaviors were likely driven by their shared method of parent-reported measurement. Results suggest that children experience restricted and repetitive behaviors in ways that more closely resemble traditional obsessive-compulsive disorder-like compulsions, whereas their parents view such behaviors as symptoms of autism spectrum disorder. These findings provide guidance for better understanding, distinguishing, and ultimately treating obsessive-compulsive disorder behavior in youth with autism spectrum disorder and introduce new conceptualizations of the phenotypic overlap between these conditions.