Previous studies suggest that social relations can increase one's motivation to learn in school. However, other evidence showed that having more friends may also distract from one's academic involvement. To understand the mechanisms behind this apparent contradiction, this study identified and tested the effects of a potentially important positive and negative mediator between social relations and academic motivation. A total of 226 university students were used to test the hypothesized path model. Results showed that the impact of social relations on students' academic motivation was negatively mediated by alcohol use, but positively mediated by their place attachment to the university, although the model fit differed for women and men. Implications for social relations, school policy and freshman orientation programs are discussed.