Using vital statistics collected on brides and grooms in most U.S. states between 1970 and 1988, we show that the older men are when they marry, the more years senior to their brides they are, whether it is a first or higher-order marriage. While older men with more education marry down in age slightly more than less educated older men, the pattern of men marrying down more if they marry later holds strongly for all education groups. We consider several possible explanations for the tendency of men to marry down in age more if they are older at marriage. While we have no direct measure of beauty, we argue that the most compelling interpretation is that men, more than women, evaluate potential spouses on the basis of beauty. Since the prevailing standard of beauty favors young women, the older men are when they marry, the more they find women their own age unattractive relative to younger women, leading them to marry down in age more if they are older at marriage. The consequence for women of men’s preference for youth is more often that they remain unmarried than that they end up married to less educated men.