Legacies of an authoritarian past still leave enduring effects on voters’ political attitudes and behavior. I argue that authoritarian nostalgia is a defining factor in voter attitudes and related behavior in post-authoritarian democracies. Voters who share core values from the authoritarian past construct heightened social identity toward the past, which breeds strong attachment to authoritarian legacy parties. I test this argument with a novel measure for authoritarian nostalgia. With original data collected from South Korea and Taiwan, I provide evidence that people high in authoritarian nostalgia are more likely to identify with and feel attached to authoritarian legacy parties in order to strengthen their social identity. Using a candidate comparison analysis, I further demonstrate that voters high in authoritarian nostalgia are more attracted to candidates evoking nostalgia over those with high programmatic or ideological proximity. Results show how authoritarian nostalgia is a central determinant of political behavior in maturing democracies.