["Journal of Regional Science, EarlyView. ", "\nABSTRACT\nAs a major form of urban administrative restructuring in China, city‐county mergers dismantle boundaries between municipal districts and surrounding counties, creating more integrated local labor markets. Using longitudinal data from the China Household Finance Survey and a difference‐in‐differences framework, we examine how this restructuring affects gender disparities in labor market outcomes. We find that the reform significantly widens the gender wage gap. Mechanism analysis shows that this gap is driven by several channels, including increased labor competition from migrant inflows, the expansion of manufacturing activity, improvements in transportation infrastructure, and rising housing values. The effects are highly heterogeneous: rural and less‐educated women, as well as women in more developed counties, experience the largest losses relative to men.\n"]