A great deal of time and money has been spent to understand why adolescents abuse alcohol. Some of the most fruitful work considers the social context navigated by adolescents, including family, school, and peer contexts. However, most of this work focuses on differences between adolescents in these contexts. The present study adds to the literature by considering within-person changes in these contexts and examines the extent to which these changes are related to alcohol use. Significant changes in all 3 contexts were observed, and these changes were significantly related to alcohol use. The significant influence of intrapersonal variability highlights the importance of attending not only to chronic, between-individual issues facing at-risk youths but emergent and transient issues that may temporarily heighten alcohol use risk. (Contains 5 tables and 1 footnote.)