This study aimed to explore how the indigenous (national) culture of teaching and learning mediates teachers' understandings of constructivism in China and the U.S. Thirty middle school math teachers who are self-identified with the mathematics teaching reform movement in each country participated in this study (NCTM 2000 Math Standards in the United States or the MOE 2001 Math Standards in China).Both theoretical and empirical methods were adopted for this research. Theoretical analysis led to a new cultural model that helped select appropriate cultural elements for this study. Based on emergence theory, the new model perceives Confucianism and Taoism as the most influential beliefs and values in terms of teaching and learning in China, in contrast with Behaviorism and Individualism in the U.S. This study revealed that the indigenous culture of China and U.S. greatly influenced teachers' understandings of teaching and learning. Chinese participants tended to advocate Eastern belief that math learning develops through mental struggle, and is facilitated by providing hints, whereas their American counterparts tended to have faith in the Western belief that properly sequenced instruction supplemented by general encouragement of students will lead to learning. However, in some cases teachers' responses defied the predictions of the cultural model. For instance Chinese and American teachers both tended to opt for the Eastern belief of creating pedagogical balance as opposed to the Western belief in choosing a single well-chosen method. The differences and commonalities between Chinese and American participants' understandings of learning and teaching are thoroughly explored in this study. The key issue of transportability of recommended pedagogical practices across cultural boundaries is discussed in the Conclusions section. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]