This article argues that investment in female education not only reduces the gender gap, but also leads to greater efficiency, increasing production, and higher income. The study is based on human capital theory, with an emphasis on gender. Secondary data was utilized. The findings reveal that increased education similarly affect women and men’s wage levels, however, greater investment in higher levels of education (because of increasing financial and opportunity costs) produce lower returns. Given the fact that the average education level of women in Iran and most of the world is less than men, female education has a greater final output than male education. Additionally, economists believe that female education has a higher social return because of the important role educated women play in promoting the health, well-being, and education of their children. Educated women are more active in the labor force, in production and income-generating activities, pay more taxes and as such, contribute to the expansion of the tax base.