Gender gaps in labor market outcomes remain substantial. A growing literature points to the possibility that gender norms shape household specialization and labor market outcomes. Yet evidence on the importance of these norms remains largely indirect. We develop and estimate a collective household model in which individuals derive utility from conforming to perceived norms regarding the division of domestic labor. To identify the strength of these norms, we combine Danish administrative data with a novel survey that measures household time allocation, perceived peer norms and responses to randomized hypothetical norm changes. The experimental variation allows us to directly estimate the costs and benefits of conforming to gender norms and quantify the importance for household behavior.