Abstract We investigate how culture affects gender differences in willingness to compete in a large pre-registered experiment using an epidemiological approach. Our sample of 1,943 Norwegians with parents born in 59 different countries shows a smaller gender gap in willingness to compete among individuals of more gender-equal ancestries. The difference is driven by women with parents from more gender-equal countries wanting to compete more and men with the same ancestry wanting to compete less. The results are robust to controlling for a large set of factors at the individual, parental and ancestral country levels, indicating that gendered culture shapes competitive preferences.