This research focuses on the development of advertising in interwar period Japan (between World War I and World War II) and the growing prevalence of the Modern Girl. As women with a certain aesthetic were popularized through advertisement campaigns, this aesthetic was disseminated to a wider audience and incited cultural change. For the purposes of this research, the cosmetics company Shiseido and its advertisements will be used in order to illustrate the effects of one major Japanese company on the spread of the Modern Girl throughout Japan and the surrounding regions. Advertisements from an MIT database were examined from the period, and are analyzed in the following work I have attempted to gauge the prominence of the Modern Girl figure, her appearance, and various other visual factors. After conducting this project, I have concluded that Shiseido played an integral rote in the rise of Japanese beauty culture and in the spread of the Modern Girl phenomenon.