Using standardized tests and surveys of eighth graders in China and the United States, this study explores the relationships among family income, parenting, home environment, and mathematics achievement. Focusing on Chinese only children and American children with no more than one sibling, the study found that the mathematics achievement of Chinese eighth graders is higher than American students. Chinese parents had higher expectations for their children and talked more frequently with them about school. Furthermore, the relationship between parental expectations and mathematics scores is stronger for Chinese students than for American students. China's national curriculum, well-trained elementary and secondary school mathematics teachers, high parental expectations, a universal concern for children's education engendered by the one child rule, and children?s willingness to work hard on mathematics are discussed as possible causes for the higher mathematics achievement of Chinese children.