Using a sample of 348 single, primarily heterosexual university students with a recent (i.e., past 10-week) hook-up experience, we examined motivations for hooking up at both a global- and event level (i.e., motivations for hook ups in general and for the participants’ most recent hook up). We also tested for differences in motivations for hooking up by gender and type of partner (i.e., stranger, acquaintance, friend, ex-romantic partner). Contrary to popular notions of hook ups as one-time sexual encounters void of attachment or emotional investment, results showed that participants were commonly motivated to hook up by the prospect of a romantic relationship. Further, the majority of motivations differed by gender; notably, women were more often motivated by the prospect of a relationship, whereas men were more often motivated by sexual experiences without obligation. Those motivated by the possibility of a romantic relationship were most likely to hook up with friends (vs. strangers, acquaintances, or ex-romantic partners), whereas hooking up due to alcohol or drug use was most likely to occur with an acquaintance compared with other partner types. Patterns of findings suggest that heterosexual men’s and women’s motivations to engage in hook ups differ considerably and that traditional gender role expectations and sexual double standards continue to be at play, which may place women at risk for poor emotional and relational outcomes following hook ups with men. (PsycInfo Database Record (c) 2020 APA, all rights reserved)