Teachers' motivation determines the quality of teachers and education. It is divided into three types based on self-determination theory (SDT). This study investigates the types and details of teachers' motivation and analyses how basic psychological needs relate to them through a case study of public primary schools in Vientiane Capital, Lao PDR. Using statistical and qualitative analyses, this study shows that SDT must be developed to explain teachers' motivation from two perspectives: the structure of teachers' controlled motivation comprises introjected regulation, and teachers' controlled motivation has a similar role to autonomous motivation in Lao PDR.