Labor and education economists have long been interested in the link between undergraduate education and earnings. In addition, studies have addressed the connections between gender and college major and GPA, as well as between gender and income. This paper brings all of these together in order to show that college major choice does have a significant effect on earnings, and that this effect differs with gender and across majors. The results show that controlling for college major, ability measures, graduation year, and GPA can help to explain a majority of the gender pay gap. Finally, the thesis then utilizes the Oaxaca-Blinder Decomposition to break down the price and composition effect of undergraduate education on the gender pay gap.