Despite its centrality to human life, health, and happiness, sleep has never been a central topic of concern to political scientists. This article proposes that chronotype (a person's time-of-sleep preference) is a previously unidentified psychological correlate of political ideology. Chronotype may lead to political ideology through a motivated social cognitive process, ideology may shape sleep patterns through a desire to align with social norms, or ideology and chronotype may arise from common antecedents, such as genetics, socialization, or community influences. Analyses demonstrate a link between a morningness and conservatism in seven American samples and one British sample. This relationship is robust to controls for openness, conscientiousness, and demographics, including age, sex, income, and education. The article concludes with a call to incorporate sleep and chronotype research into political science across a range of topics and subfields, including political psychology, social networks, political geography, political communication, political institutions, and survey design.