[[abstract]]Background: The study aims to (i) identify the evolving profile of endorsed alcohol expectancies (AEs) during the transition from late childhood into early adolescence, and (ii) examine the connection between such profiles and subsequent alcohol drinking and purchasing in adolescence. Methods: A prospective cohort of 928 sixth graders was recruited from 17 elementary schools in northern Taiwan in 2006 with follow-ups conducted in seventh and eighth grade. Information concerning AEs, individual characteristics, and social attributes were collected by self-administered questionnaires at baseline and in seventh grade; drinking behaviors and alcohol purchasing were assessed in eighth grade. Longitudinal latent profile and survey re...