Abstract Previous efforts to elucidate dispositional antecedents of organizational citizenship behaviors have yielded equivocal results. The current study presents and tests a theoretical argument for expecting conscientiousness to interact with interpersonal dimensions of personality in predicting helping behaviors. As hypothesized, the responses of 374 women and their supervisors reveal significant interactions between conscientiousness, on the one hand, and agreeableness, extraversion, and emotional stability, on the other, in predicting helping behaviors. Clarifying the relationship between personality and helping, these results suggest that the impact of conscientiousness in a social context depends on a positive interpersonal orientation. The implications of these findings for research and practice are discussed.