Alcohol consumption and interpersonal trauma (IPT) co-occur at high rates, particularly in college populations. Two non-mutually-exclusive theories of this comorbidity are the risky behavior model, suggesting that substance use increases likelihood of IPT, and the self-medication model, suggesting that individuals use substances to cope with trauma-related symptoms. Few have simultaneously tested these theories in a sample of college students. Thus, the overarching aim of this longitudinal study (n = 1320) was to identify whether alcohol consumption and IPT are associated with one another, and if IPT and/or posttraumatic stress disorder (PTSD) impacts use of alcohol to cope with trauma-related distress. Data were collected from a longitudinal study of college students attending a large public university. Participants in the current study were on average 18.46 years old at study entry, primarily female (70%), and of diverse racial/ethnic backgrounds (e.g., 49.4% White, 19.7% Black, 17.2% Asian). Results from auto-regressive, cross-lagged models indicated that alcohol consumption preceded IPT exposure. In contrast, IPT was not prospectively associated with alcohol consumption. Those reporting probable PTSD, but not IPT, reported more use of alcohol to cope with trauma-related distress. These findings provide support for the risky behavior model, indicating that those with higher levels of alcohol consumption may be a vulnerable group in terms of likelihood of IPT. Findings also suggest that those reporting probable PTSD may be at risk for use of alcohol to cope with trauma-related distress. Implications of these findings, in light of study limitations, are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).