To advance understanding of the gap in fraction learning between students in high-achieving East-Asian countries and the United States, we examined both intended curricula (i.e. standards) and implemented curricula (i.e. textbooks) in East Asia and the United States. Many similarities were present in both standards and textbooks. However, U.S. students began studying fractions earlier and studied them over more grades, and East-Asian instruction was more concen trated and included more mathematically challenging problems. Additionally, U.S. standards and textbooks tended to contextualize problems and emphasize the part–whole and measurement models of fractions, whereas East-Asian curricula tended to teach fraction concepts within the context of multiplicative reasoning and to teach fraction operations as an extension of whole-number operations. Educational implications of the findings about input are discussed.