Objective: in Colombia, many first-year university students consume unhealthy food, are physically inactive, and drink regularly, which can be associated with the behavior of social ties, living with social ties, and time with peers. The present cross-sectional study assessed the association between health behaviors of first-semester students and these factors. Method: N = 189 (Mage = 18.79; SD = 1.07; female = 68.8%) first-semester students in Colombia completed an online questionnaire investigating current and expected health behaviors as well as influencing factors. ANCOVAs, bivariate correlations, moderation analyses, and hierarchical regressions were used to analyze the data. Results: expected food consumption (stronger among participants who live with parents) as well as current and expected heavy drinking and binge drinking (stronger among participants who do not live with parents) were significantly correlated to the respective parental behavior. Current and expected drinking was significantly correlated to partners’ drinking. Expected physical activity was correlated with peers’ physical activity. Partners’ attempts to encourage drinking moderated the association between participants’ current and expected drinking with partners’ drinking. Time spent with peers was related to heavy drinking and engaging in more physical activity. Conclusion: in Colombia, parents appear to play a significant role in their offspring’s health behaviors during their first semester at university, particularly regarding food consumption and alcohol use. Partners’ drinking and time spent with peers are strongly related to heavy drinking.