Intimate partner violence (IPV) is harmful and prevalent, but leaving abusive partners is often challenging due to investments (e.g., children, shared memories). Identifying warning signs of abuse early on is one prevention strategy to help people avoid abusive long-term relationships. Using university and online samples, the present studies identified warning signs and protective factors that predicted overall, physical, psychological, and sexual abuse cross-sectionally (Study 1) and prospectively over 6 months (Study 2). These studies demonstrated that the number of warning signs a person experienced and the frequency with which they experienced those warning signs predicted overall abuse. Seven warning signs emerged as predictors in both studies (e.g., “My partner acted arrogant or entitled”), suggesting that they are particularly important for identifying potentially abusive relationships. This is the first research to identify warning signs that prospectively predict abuse; findings have implications for IPV prevention efforts in academic and public contexts.