This study examined whether attachment and self-change predict relationship stability and whether relationship stability differs according to gender. The research data consisted of 403 participants, both online and face-to-face. Multiple linear regression analysis was conducted to determine the predictive power of self-change and attachment on relationship stability in university students. Independent samples t-test was conducted to determine whether there was a difference in the relationship stability levels of the participants according to gender. According to the findings obtained from the analysis, university students' self-expansion, self-contraction, anxious attachment, and avoidant attachment levels significantly predict relationship satisfaction. Self-expansion, self-adulteration, self-contraction, and anxious attachment significantly predict the level of evaluation of the quality of options. Self-expansion, self-contraction, self-adulteration, anxious attachment, and avoidant attachment significantly predicted relationship investment, whereas self-expansion, self-contraction, self-adulteration, and avoidant attachment significantly predicted commitment. In addition, men's relationship satisfaction and relationship investment levels are significantly higher than women's. The findings were discussed and interpreted in line with the literature on relationship stability, and some suggestions were presented for researchers and practitioners.