Background Intimate partner violence (IPV) harms the health of women and their children. In Vietnam, 31% of women report lifetime exposure to physical IPV, and surprisingly, women justify physical IPV against wives more often than do men. Objective We compare men’s and women’s rates of finding good reason for wife hitting and assess whether differences in childhood experiences and resources and constraints in adulthood account for observed differences. Methods Probability samples of married men (N = 522) and women (N = 533) were surveyed in Vietnam. Ordered logit models assessed the proportional odds for women versus men of finding more “good reasons” to hit a wife (never, 1–3 situations, 4–6 situations). Results In all situations, women found good reason to hit a wife more often than did men. The unadjusted odds for women versus men of reporting more good reasons to hit a wife were 6.55 (95% CI 4.82 – 8.91). This gap disappeared in adjusted models that included significant interactions of gender with age, number of children ever born, and experience of physical IPV as an adult. Discussion Having children was associated with justifying wife hitting among women but not men. Exposure to IPV in adulthood was associated with justifying wife hitting among men but was negatively associated with justification of IPV among women. Further study of the gendered effects of resources and constraints in adulthood on attitudes about IPV against women will clarify women’s more frequent reporting than men’s that IPV against women is justified.