A novel version of Snijders's stochastic actor‐based modeling (SABM) framework is applied to model the diffusion of first alcohol use through middle school–wide longitudinal networks of early adolescents, aged approximately 11–14 years. Models couple a standard SABM for friendship network evolution with a proportional hazard model for first alcohol use. Meta‐analysis of individual models for 12 schools found significant effects for friendship selection based on the same alcohol use status and for an increased rate of onset to first use based on exposure to already‐onset peers. Onset rate was greater at higher grades and among participants who spent more unsupervised time with friends. Neither selection nor exposure effects interacted with grade, adult supervision, or gender.