The relationship between women's attitudes toward gender equality and their fertility aspirations has been researched extensively, but few studies have explored the same associations among men. Using recent Demographic and Health Survey data from five high fertility East African countries, we examine the association between young men's gender attitudes and their ideal family size. Whereas several DHS gender attitude responses were associated with fertility aspirations in select countries, men's greater tolerance of wife beating was consistently associated with higher fertility aspirations across all countries, independent of education, income, or religion. Our findings highlight the overlapping values of male authority within marriage and aspirations for large families among young adult males in East Africa. Total lifetime fertility in East Africa remains among the highest worldwide: thus, governments in the region seeking to reduce fertility may need to explicitly scrutinize and address the reproduction of prevailing masculine values.