<p>The ancient Roman Republic was the longest-lived popularly governed state in human history yet is understudied in democracy research. This essay provides a systematic overview of the Republic’s political institutions and practices, assembling recent historical evidence in a form accessible to democracy scholars. I argue that, by the criteria used to classify classical Athens and the United States as democracies, the Roman Republic was also a democracy. To substantiate this claim, I combine qualitative analysis of its institutions and practices with quantitative evidence, calculating democracy index scores using the Polity5 rubric and the Economist Intelligence Unit rubric, both of which classify the Republic as a democracy. The essay highlights several unique features of the Republic’s institutions that may have contributed to its longevity, and its ability to flourish in the competitive ancient Mediterranean world.</p>