Vietnam’s economic boom during the transition to a market economy has centered on very rapid growth in some sectors and some provinces, yet poverty has diminished across the entire country. With capital investments highly concentrated by province and sector, geographic labor mobility may be critical in spreading the gains from growth. Conversely, rising income inequality may be attributable in part to impediments to migration. We first use census data to investigate migration patterns and determinants. We then examine the role of migration as an influence on cross-province income differentials. The former analysis robustly confirms economic motives for migration but also suggests the existence of poverty-related labor immobility at the provincial level. Examination of income differentials between pairs of provinces reveals that the impact of migration on inequality can be either negative or positive. A robust inequality-reducing impact of migration is found for migration flows into provinces where most of Vietnam’s trade-oriented industrial investments are located.