This study examines Indonesian primary teachers' mathematical knowledge for teaching geometry and what factors contribute to this knowledge. A translated and adapted version of the Learning Mathematics for Teaching measures and the Indonesian Educational Survey were used to gather information on teachers' knowledge for teaching geometry and their background information. Based on statistical analyses (ANOVA and multiple regression model) teachers' mathematical knowledge for teaching differs by their educational attainment and grade range taught. Implications include capping the minimum education requirement to a four-year college degree and requiring teachers to teach several grade levels over a period of time. (Contains 3 tables and 2 figures.)