The impact of the International Baccalaureate (IB) curriculum on Chinese teachers' self-efficacy has been unknown. The purpose of this causal-comparative study was to determine the impacts of the International Baccalaureate curriculum on Chinese teachers' reports of self-efficacy. Two groups were studied, the first comprised Chinese public schoolteachers who are Chinese nationals, licensed to teach in China, and teach between grades 1 to 9; the second consisted of IB teachers who met these same criteria but also worked in an authorized IB school and attended at least one IB authorized training. Teacher self-efficacy was measured using the Teachers' Sense of Efficacy Scale (TSES). A two-sample t test determined there was a significant difference in self-efficacy levels between IB and public school Chinese teachers. Post hoc analysis indicated small to large effect sizes for all subcategories of the TSES.