In two studies, we identified predictors of staying friends with an ex‐partner, developed and validated a measure for reasons to stay friends with exes, and examined the outcomes of staying friends. We identified four reasons to stay friends with exes: Security, Practical, Civility, and Unresolved Romantic Desires. Sex, sexual orientation, attachment styles, personality traits, time since breakup, and reasons for breakup all predicted staying friends. Staying friends due to Unresolved Romantic Desires resulted in negative outcomes, whereas staying friends due to Security and Practical reasons resulted in more positive outcomes. Staying friends due to Practical or Civility reasons resulted in the friendship being less likely to last in the long term. Implications for future research and clinical work are discussed.