This paper traces the development of Thailand’s agricultural sector over the past four decades. Factors contributing to agricultural productivity changes are discussed. Productivity growth in agriculture lags behind manufacture, preventing a natural transfer of agricultural workers to the non-agricultural sector. The changing pattern of competitiveness of Thailand’s agricultural exports is analyzed by focusing on their growth and world market shares. The results indicate that the Thai agricultural sector can still maintain competitiveness in some commodities. While traditional commodities may lose their importance in the future, new agricultural products would emerge. Exports of agricultural products have been diversified over the years, while their ability to compete in the world markets has been enhanced. Processed food industry would be the key to the future of Thailand’s agriculture, but maintaining export competitiveness requires constant upgrading of food-safety standards. Agricultural growth alone cannot reduce rural poverty; it must be accompanied by growth in non-agriculture. Dynamism of the Thai agriculture and its survival depend primarily on continued productivity improvement.