The reform of China’s one-child policy allows families to have more children and thus may affect anticipation of intergenerational succession of family businesses and drive family firms to improve their corporate social responsibility (CSR). Using a difference-in-differences design, we find that the reform positively affects family firm CSR. We also find that the positive impact is more pronounced for family firms whose owners have fewer children, have no son, and are of reproductive age, which confirms the theory that intergenerational succession anticipation drives family firm CSR. Moreover, we find that the positive impact is more pronounced for firms that operate in environments where CSR is more strategically important. We validate our findings by showing that the reform curtails family firms’ short-termism.