ABSTRACT The Guatemalan National Revolutionary Unit (URNG) fought one of the longest and bloodiest civil wars in recent Latin American history. In 1996, the URNG and the Government of Guatemala signed a Firm and Lasting Agreement ending the country’s civil war and initiating the URNG’s post-war life as a political party. After finishing third in its initial electoral competition, the URNG has since been unable to capture more than 4% of the vote, on its own or in coalition, leaving it a minor political party. What explains the poor electoral performance of the URNG as a political party? Based upon fieldwork, elite interviews, and analysis of electoral data, I argue that the URNG’s minor party performance was caused by both organizational and institutional factors.