Traditional gender norms can restrict independent migration by women, thus preventing them from taking advantage of economic opportunities in urban areas. To explore this phenomenon, we develop a model in which women make marriage and migration decisions jointly. The model shows that, in response to a decline in the economic cost of migration, women may use marital migration to circumvent social barriers to female independent migration. To test this and related hypotheses, we use the construction of a major bridge in Bangladesh - which dramatically reduced travel times between the economically deprived north-western region and the capital city Dhaka - as a source of variation in migration costs. Consistent with the predictions of the model, we find that, among rural women from wealthier families, the bridge increased marital migration, schooling, dowry payments, and work in the manufacturing sector, but had no effect on economic migration.