Unwanted pursuit behaviours (UPBs) comprise repeated and unwanted efforts to establish intimate contact in the form of harassing, tracking, and monitoring. These are common among young adults following the breakup of a romantic relationship, typically by the rejected partner. The relational goal pursuit theory (RGPT) proposes that UPB users overestimate the importance of a relationship to higher-order goals. This study assessed how well a new coping-based approach and the RGPT model predicted UPB frequency and scope. Two hundred participants (50% female; aged 19–24) completed an anonymous online survey. Ruminating was linked to both greater frequency and scope of UPB use. Higher levels of emotion-focused coping and perceived self-efficacy to re-establish intimacy were linked to the use of a wider scope of unwanted pursuit behaviours. Insights gained from UPB users are necessary for understanding mechanisms associated with the turbulent and distressing aftermath of a romantic breakup.