The outcome of the 2016 US presidential election cycle generated a great deal of attention about the political psychology of the average American voter. A familiar narrative was that authoritarianism, perhaps triggered by fears of cultural and economic change, was the primary driver of support for Donald Trump. This article argues that sexism has been underestimated as a political force, especially given the angry emotional climate. The article first explores the electoral role of sexism early in the campaign, finding that sexism powerfully predicted vote choice even after controlling for authoritarianism, partisanship, and other predispositions. Second, the article analyzes American National Election Studies time-series data to examine the impact of sexism in recent presidential elections, demonstrating that 2016 was the only year in which it played a large and significant role. Finally, a survey experiment tests the theorized causal mechanism underlying sexism’s influence: the catalyzing power of anger versus fear. Fear sharply reduced sexism’s impact on support for Trump relative to those who experienced anger. Further, anger powerfully mobilized sexists, a group that would normally be likely to stay home. These results illuminate the role that emotional undercurrents play in catalyzing group-based predispositions into politics.