Objective: Risk for suicide is often higher among college students, compared to same-age noncollegiate peers, and may be exacerbated by quality of social support and interactions. The authors examined the independent contributions of positive social support and negative social exchanges to suicide ideation and attempts in college students. Participants: Participants were 439 volunteer undergraduate students, who were primarily female (71%). Methods: Cross-sectional, survey design. Participants completed measures assessing positive social support, including emotional, informational, and tangible support; negative social exchanges; and suicidal behavior, including ideation and attempts. Results: Positive social support, particularly tangible support, and negative social exchanges were significantly predictive of greater suicidal behavior. Conclusions: Practical manifestations of support may buffer against suicide risk for college students, whereas conflict-based interactions may contribute to increased risk. At the institutional, parental, and peer levels, promotion of supportive relationships may be an important suicide prevention strategy. (Contains 2 tables.)