Women perform most of the housework despite substantial convergence in labor market outcomes. We develop and estimate a semi-structural model of household housework decisions that combines randomized vignette experiments with an epidemiological identification strategy to estimate the contributions of economic utility and social norms. Equal sharing of housework yields higher economic utility for both men and women, while households use domestic work to offset differences in labor market involvement. Yet women continue to perform a disproportionate share of housework, largely because of social norms. Exposure to more egalitarian gender norms significantly increases the likelihood of more balanced housework allocations.