The authors argue that individual differences in men's Benevolent Sexism (BS) stem from a threat-driven security-cohesion motivation, indexed by Right-Wing Authoritarianism (RWA), whereas Hostile Sexism (HS) stems from a competitively driven motivation for intergroup dominance, indexed by Social Dominance Orientation (SDO). In Study 1, meta-analysis indicated that men's SDO (controlling for RWA) was moderately positively associated with HS (r = .35) but not BS (r = .05), whereas men's RWA (controlling for SDO) was moderately associated with BS (r = .36) but only weakly associated with HS (r = .16). Study 2 replicated and extended these results by also modeling the dual personality traits and world-views underlying HS and BS. In Study 3, longitudinal analyses demonstrated that SDO predicted increases in HS (but not BS) and RWA predicted increases in BS (but not HS) throughout a 5-month period. Relations between the sociostructural and individual difference bases of men's ambivalent sexism are discussed.