This article examines the effectiveness of teacher education programs from fifteen countries with respect to mathematics content knowledge (MCK) and mathematics pedagogical content knowledge (MPCK) as cognitive outcomes after equalizing their teacher intake. Data from the comparative TEDS-M study revealed that the mathematics content knowledge (MCK) and the mathematics pedagogical content knowledge (MPCK) of primary teachers differed significantly at the end of teacher education between the participating countries and between teacher education programs within countries.