Entrepreneurship is a key source of economic growth. In this paper, we study the (neglected) role of mating competition in promoting entrepreneurship. We examine data from China because the country provides unusual variations across regions in the degree of mating competition due to differentially skewed sex ratios. Since family wealth is an important status variable in the marriage market, the sex ratio imbalance has created a powerful additional incentive for wealth creation. We provide evidence that the imbalance promotes entrepreneurship and hard work. First, new domestic private firms are more likely to emerge from regions with a higher sex ratio imbalance. Second, the likelihood for parents with a son to be entrepreneurs rises with the local sex ratio. Third, households with a son in regions with a more skewed sex ratio demonstrate a greater willingness to accept relatively dangerous or unpleasant jobs and supply more work days. In contrast, the labor supply pattern by households with a daughter is unrelated to the sex ratio. Finally, regional GDP tends to grow faster in provinces with a higher sex ratio. We estimate that the skewed sex ratio contributes about 20% to the overall growth rate in recent years. Since the sex ratio imbalance will become worse in the near future, this growth effect is likely to persist.