This chapter describes longitudinal findings from a socially diverse sample of 125 British children seen at ages two and four. Four models of social influence on executive function are tested, using multiple measures of family life as well as comprehensive assessments of children’s executive functions. Our results confirm the importance of maternal scaffolding for young children’s executive functions, but they also suggest positive effects of observational learning and adverse effects of disorganized and unpredictable family life; however, no support was found for an association between executive function and general positive characteristics of family interactions.