Gender remains a key predictor of housework in modern society. However, previous studies have been relatively limited in their ability to adjudicate between possible mechanisms operating at the individual and social-interactional level that may cause this relationship. To address this gap, we employ a novel experimental design in which respondents view and evaluate photos of a relatively clean or messy room, which is ostensibly occupied by either a man or a woman. We find that men and women respondents do not differ in their perceptions of how messy a room is or how urgent it is to clean it up. In contrast, the gender of the room occupant has strong and significant effects on housework perceptions, moral judgments, perceived social consequences, and allocations of responsibility. Notably, when a relatively clean room is evaluated, female room occupants are held to higher standards of cleanliness, are believed to suffer more negative social consequences when they do not meet those standards, and are generally deemed more responsible for housework across a variety of work-family arrangements than their male counterparts. However, when a messy room is evaluated, gender effects are smaller and less systematic, in part because messiness activates negative stereotypes about men. Overall, findings underscore and refine the theory that gendered beliefs and accountability practices are a root cause of gendered behavior in the household.