Our aim was to investigate two personality traits (i.e., stoicism and sensation seeking) that may account for well-established gender differences in suicide, within the framework of the interpersonal theory of suicide. This theory proposes that acquired capability for suicide, a construct comprised of pain insensitivity and fearlessness about death, explains gender differences in suicide. Across two samples of undergraduates (N = 185 and N = 363), men demonstrated significantly greater levels of both facets of acquired capability than women. Further, we found that stoicism accounted for the relationship between gender and pain insensitivity, and sensation seeking accounted for the relationship between gender and fearlessness about death. Thus, personality may be one psychological mechanism accounting for gender differences in suicidal behavior.