Difficulties with social communication and interaction are a hallmark feature of autism spectrum disorder. These difficulties may be the result of problems with explicit social cognition (effortful and largely conscious processes) such as learning and recalling social norms or rules. Alternatively, social deficits may stem from problems with implicit social cognition (rapid and largely unconscious processes) such as the efficient integration of social information. The goal of this study was to determine how problems in explicit and implicit social cognition relate to social behavior in 34 youth with autism spectrum disorder. We measured aspects of implicit and explicit social cognition abilities in the laboratory using behavioral, cognitive, and brain (electrophysiological) measures. We then used those measures to predict “real-world” social behavior as reported by parents, clinicians, and independent observers. Results showed that overall better aspects of implicit and explicit social cognition predicted more competent social behavior. In addition, the ability to fluidly integrate social information (implicit social cognition) was more frequently related to competent social behavior that merely knowing what to do in social situations (explicit social cognition). These findings may help with the development of interventions focusing on improving social deficits.