When a romantic relationship ends, individuals often look back and wish they had done things differently. What may seem clear in hindsight, however, is often unclear in foresight. We investigated the effects of outcome knowledge on individuals’ judgments of a dating couple. In Study 1 (181 U.S. college students, 334 U.S. community adults), participants read about a couple with an uncertain relationship trajectory; then, experimental group participants received knowledge about the couple’s status six months down the road as broken up or still together, while control group participants received no outcome knowledge. Individuals who were told the dating couple broke up perceived that outcome as more likely and obvious compared to those who were not given outcome knowledge or who were told the couple stayed together. In Study 2 (262 U.S. college students, 333 U.S. community adults), participants in the experimental conditions received knowledge about the couple’s status six months later as broken up or engaged, while control group participants received no outcome knowledge. In both samples, outcome knowledge of a breakup had a negative effect on individuals’ judgments about the couple. Among community adults, but not among college students, outcome knowledge of an engagement positively affected judgments of the couple. We offer directions for future research and discuss the mechanisms by which hindsight bias might affect evaluations of our own and others’ relationships.