ABSTRACT. Objective: The current study develops an empirically determined classifi cation of sexual orientation developmental patterns based on participants' annual reports of self-identifi cations, sexual attractions, and sexual behaviors during the fi rst 4 years of college. A secondary aim of the current work was to examine trajectories of alcohol involvement among identifi ed subgroups. Method: Data were drawn from a subsample of a longitudinal study of incoming fi rst-time college students at a large, public university (n = 2,068). Longitudinal latent class analysis was used to classify sexual minority participants into empirically derived subgroups based on three self-reported facets of sexual orientation. Multivariate repeated-measures analyses were conducted to examine how trajectories of alcohol involvement varied by sexual orientation class membership. Results: Four unique subclasses of sexual orientation developmental patterns were identifi ed for males and females: one consistently exclusively heterosexual group and three sexual minority groups. Despite generally similar alcohol use patterns among subclasses, certain sexual minority subgroups reported elevated levels of alcohol-related negative consequences and maladaptive motivations for use throughout college compared with their exclusively heterosexual counterparts. Conclusions: Elevations in coping and conformity motivations for alcohol use were seen among those subgroups that also evidenced heightened negative alcohol-related consequences. Implications and limitations of the current work are discussed. (J. Stud. Alcohol Drugs, 73, 290-302, 2012) Received: May 16, 2011. Revision: November 9, 2011. This research was supported by National Institute on Alcohol Abuse and Alcoholism Grants K99 AA019974 (to Amelia E. Talley); F31 AA019596 (to Andrew K. Littlefi eld); and T32 AA13526, R37 AA07231, and KO5 AA017242 (to Kenneth J. Sher).*Correspondence may be sent to Amelia E. Talley at the Department of Psychological Sciences, University of Missouri, Columbia, MO 65211 or via email at: Talleyae@missouri.edu. S EXUAL MINORITY INDIVIDUALS (i.e., those who endorse a nonheterosexual self-identifi cation or same-sex sexual attractions or behaviors) tend to show higher levels of substance use (Bux, 1996;Marshal et al., 2009;Paul et al., 1991;Talley et al., 2010). Alcohol use disparities may be more pronounced for female sexual minority members (Corliss et al., 2008;Eisenberg and Wechsler, 2003; Marshal et al., 2008) compared with their male counterparts. These disparities are thought to contribute to increased risk of suicide attempts (Hegna and Wichstrøm, 2007;Russell and Joyner, 2001; cf. Silenzio et al., 2007) and ideation (Silenzio et al., 2007), elevated frequencies of risky sexual behaviors (e.g., Meyer and Dean, 1995; cf. Weatherburn et al., 1993), and other adverse consequences.Several hypotheses attempt to explain vulnerability to alcohol misuse among sexual minorities (for reviews, see Bux, 1996;Hughes and Eliason, 2002), including coping with s...