Using data from the German Family Panel (pairfam; n = 3,674 heterosexual couples), this study examines the impact of partners' individual levels and dyadic similarity concerning life goals, values, and personality traits on relationship satisfaction and union dissolution. Controlling for partners' individual characteristics and for relationship duration, it was found that similarity on specific dimensions and stereotype‐adjusted profile correlations exerted significant yet small positive effects on both partners' relationship satisfaction. These effects largely translated into beneficial indirect effects on union dissolution 1 year later (Wave 2, n = 2,820). Moderator analyses indicated the existence of some effect heterogeneity across relationship duration and types. Generally, partners' respective individual characteristics appeared to predict relationship outcomes better than dyadic similarity measures.