In the United States, women’s persistent gains in structural power may cause backlash among those motivated to preserve the status quo. The proposed study examines the conditions that prompt men and women to endorse sexism and promote gender stereotypes. System justification theory proposes that people are motivated to justify the socio-political system that governs them and threats to the stability of their system can increase individual’s motivated defenses. I expect men to show the strongest motivated defenses when the hierarchy is threatened or viewed as unstable, because to protect group-based interests men will reinforce the legitimacy of the system through stronger endorsement of system defenses. In contrast, women will show the strongest system defenses when the hierarchy is viewed as stable, to avoid feeling trapped in an unchanging system that oppresses them. To test these ideas, 430 men and women were exposed to a gender status hierarchy that was portrayed as stable or unstable and then they responded to several measures of sexism and gender stereotypes. Support for the hypothesis was only found on one measure of gender stereotypes. Men reported more system justifying stereotypes of traditional women in the unstable condition, while women showed the opposite pattern. Exploratory results demonstrate that men’s and women’s reports of agentic stereotypes for traditional and nontraditional women depended on whether they were exposed to a stable or unstable gender hierarchy. Future directions and limitations are discussed in consideration of these exploratory findings.