Using time-series data spanning three decades, we examine the determinants of sectoral migration in Indonesia, Thailand, and the Philippines. We used a principal-components algorithm to address the problems associated with trended and intercorrelated explanatory variables. Migration rates in the three countries are low relative to other developing countries, with the consequence of persistent intersectoral income differentials. Even so, the rate of migration has been responsive to the income ratios in each country. The migration rates were also affected by the absorbing capacity of nonagriculture, as indicated by several measures. In contrast to other studies, policy variables consisting of indicators of physical and human capital had little impact on the migration rate separate from that captured by relative incomes.