This paper reports a study on politeness strategies American English speakers and Chinese speakers use to respond to compliments. It has three aims: (1) to discover similarities and differences of politeness strategies between the two groups, (2) to provide empirical evidence for or against existing theories of linguistic politeness, and (3) to reveal differences of social values between the two cultures. The two groups were found to use largely different politeness strategies: the American English speakers' strategies are mostly motivated by Leech's Agreement Maxim, whereas the Chinese speakers' strategies are motivated by his Modesty Maxim. This difference is then related to differences of social values between the two cultures, particularly in their respective beliefs about what constitutes self-image. The findings of this study point to some inadequacies of Brown and Levinson's (1987) model of politeness, since it cannot explain all strategies used by the two groups of subjects, particularly those used by the Chinese speakers. Gu's (1990) model, on the other hand, accounts for the Chinese data well, but cannot explain most of the American English speakers' strategies. Leech's (1983) Politeness Principle is shown to be the most adequate model to analyze the data of the present study.