The objective of this research is to investigate the association between family firms and corporate social performance and whether corporate governance moderates this association. The sample includes U.S. listed companies from 2004 to 2013. The empirical results show that family firms have weaker corporate social performance than non-family firms. This finding is consistent with the notion of entrenchment effect, which means family firms have greater conflict of interest between controlling insiders and non-controlling outside investors (i.e., Type 2 agency problem). We also find that the above association mainly comes from poorly-governed family firms, suggesting that better corporate governance can mitigate the Type 2 agency problem.