Familiarity is attractive in many types of stimuli and exposure generally increases feelings of liking. However, men desire a greater number of sexual partners than women, suggesting a preference for novelty. We examined sex differences in preferences for familiarity. In Study 1 (N = 83 women, 63 men), we exposed individuals to faces twice and found that faces were judged as more attractive on the second rating, reflecting attraction to familiar faces, with the exception that men's ratings of female faces decreased on the second rating, demonstrating attraction to novelty. In Studies 2 (N = 42 women, 28 men) and 3 (N = 51 women, 25 men), exposure particularly decreased men's ratings of women's attractiveness for short-term relationships and their sexiness. In Study 4 (N = 64 women, 50 men), women's attraction to faces was positively related to self-rated similarity to their current partner's face, while the effect was significantly weaker for men. Potentially, men's attraction to novelty may reflect an adaptation promoting the acquisition of a high number of sexual partners.