It is widely believed that couples look alike. Consistently, previous research reported higher facial similarity for couples than non-couples, and that facial similarity predicts marital satisfaction. However, it is unclear if facial similarity in couples shown in previous studies was solely driven by extrinsic features like hairstyle, glasses, etc. Also unclear is what attributes are perceived as similar from the faces of a couple. In three experiments, we showed that faces were considered more similar in couples than non-couples even without extrinsic features. Personality and age perceived from faces were also more similar in couples. Importantly, by matching pairs of faces according to their perceived personality, we found that a higher similarity in the perceived personality of a face pair led to higher facial similarity and couple likelihood ratings. These findings suggest that, instead of a result of pure physical analyses, facial similarity in couples is partly based on active social cognitive judgments on perceived personality, which may reveal the actual personality of the couples and thus inform relationship quality.