International comparatives studies in education provide a fresh perspective on K-12 education policy be enabling countries to learn from each other's approaches. The recently conducted Teacher Education and Development Study-Mathematics (TEDS-M) provided us with a world-wide lens to examine some of our practices related to the preparation of U.S. teachers of mathematics for elementary and middle school students. More specifically, by looking at the top performing teacher preparation programs internationally we found a comment set of learning experiences. These empirically derived standards can be used to examine the quality of the preparation of future U.S. teachers in various university and college programs. Analyses based on the TEDS and TEDS follow-up studies indicate considerable variation in the rigor of U.S. teacher preparation programs (especially for middle school), and that the coursework of future teachers can have a significant impact on their preparation to teach mathematics. [The work in this paper was jointly supported by the Center for the Study of Curriculum and the Education Policy Center.]