Maize is one of five major crops grown in the uplands of Thailand, along with rice, cassava, sugar cane, and rubber trees. Government-promoted crop diversification, increased population growth, improved transportation networks, inter national trade, expansion of upland farming areas, and increased demand for grains from the domestic livestock and poultry industry stimulated Thailand’s maize production beginning in the 1980s. However, Thailand’s domestic maize supply is currently not sufficient to meet the needs of its in-country demands, and small quantities have to be imported. This study characterized the social and biophysical maize production environment of Thailand; examined its response to increasing maize demand; determined constraints to future productivity growth; indicated the potential environmental consequences, and examined the options available for promoting sustainable growth in maize production.