Objectives: This systematic review and meta-analysis evaluates the effectiveness of bystander programs that address sexual violence on college campuses. Program effects on student attitudes/beliefs and bystander behavior were examined. Durability of program outcomes and the influence of program-delivery methods (e.g., facilitator-led programs vs. video, online or poster campaign programs) and program-parameters (e.g., program length) were also evaluated. Methods: Twenty-four studies met criteria for inclusion in the meta-analysis, and 207 separate results from these studies were coded. Results: Students who participated in a bystander program, compared to those who had not, had more pro-social attitudes/beliefs about sexual violence and intervening to prevent it, and engaged in more bystander behavior. Program effects diminished over time, but meaningful changes persisted for at least three months following program delivery. Longer programs had greater effects than shorter programs on attitudes/beliefs. Conclusions: Bystander programs can be a valuable addition to colleges' violence prevention efforts.