Women continue to be underrepresented in politics, even in countries with relatively high gender equality such as within the borders of Europe. A major contributor to this underrepresentation is that women have lower political ambition than men, i.e., women are less interested in and willing to become political candidates. Moreover, the political domain remains highly masculinised, undervaluing the issues that disproportionately impact women and undervaluing feminine leadership traits. Both men and women in politics are part of perpetuating the stereotypical and limited image of what politics is and what politicians should do. Women’s descriptive (numeric), symbolic and substantive political representation are therefore harmed by supply-side factors. In this thesis, supply-side refers to those factors that impact the choices of potential political candidates and actual political candidates in ways that limit the quantity and quality of women’s political representation. This thesis tests the potential impact of media discrimination against women on the supply-side of women’s political representation. Media discrimination in political news includes underreporting on women, using stereotypical gender portrayals, disproportionately criticising female politicians and objectifying women. While the literature gives reason to expect both politically activating and deactivating effects of discrimination exposure on women, there are extremely few studies testing potential media effects on men and women’s political ambition. Likewise, there are extremely few studies testing whether gendered campaign environments impact the way future candidates choose to behave within the political domain. Using data from two experimental studies and content analyses, this thesis highlights both the resilience of women in the face of media discrimination, and simultaneously the way media discrimination hinders progress towards putting femininity on an equal footing with masculinity in the political domain.