In 1980, Zimbabwe rapidly expanded access to secondary schools, providing a natural experiment to estimate the impact of increased maternal secondary education on child mortality. Exploiting age specific exposure to these reforms, we find that children born to mothers most likely to have benefited from the policy were about 21% less likely to die than children born to slightly older mothers. We also find that increased education leads to delayed age at marriage, sexual debut, and first birth and that increased education leads to better economic opportunities for women. We find little evidence supporting other channels through which increased education might affect child mortality. Expanding access to secondary schools may greatly accelerate declines in child mortality in the developing world today.