Despite the public health importance of alcohol-free social programs for college students, the majority of existing campus strategies have not been empirically evaluated. This study utilized repeated daily reports to examine the association between attendance at campus-led alcohol-free programming and alcohol use on specific days while controlling for individuals' typical rates of use. The current study assessed students' participation in the LateNight Penn State (LNPS) alcohol-free programming and amount of alcohol use at a daily level, in order to determine whether students consumed less alcohol on days they attended LNPS compared to weekend days they did not attend. First-year college students reported their daily social activity involvement and alcohol use via 14 consecutive daily web-based surveys. Multilevel regression analyses modeled variation in alcohol use on weekend days (N = 3,350) nested within people (N = 689 people, 51% women). Analyses focused on within-individual differences between nights attending and not attending LNPS, thereby controlling for stable individual differences, measured and unmeasured. Results indicated that students drank less on days they attended LNPS and on days they stayed in (rather than going to bars/parties, other campus events, or entertainment), both especially among women. These results suggest that alcohol-free social programs may be an effective strategy for decreasing alcohol use on days when students attend alcohol-free events rather than going to other events or gatherings.