Using a clean setting in China, we test the Miller (1977) hypothesis that stocks are overvalued in the presence of short sale constraints and dispersion of opinion as an extension of Berkman et al. (2009). We find that stocks with short sale constraints have significantly negative abnormal returns during earnings announcement periods, especially when investors have diverse opinions. These results are robust to alternative measures of abnormal returns and endogeneity concern. The findings help to explain the impact of short sale constraints on pricing efficiency and have important policy implications for relaxing restrictions on short selling and improving regular information disclosure in emerging markets.