Authenticity has emerged over recent decades as a prominent theme in both the press and in political research—and peaked in the 2016 presidential contest that pitted Donald Trump against Hillary Clinton, Bernie Sanders, Marco Rubio, and Ted Cruz. In this context, we attempted to answer the question: How do voters judge a presidential candidate's authenticity? Here we use motivated reasoning and correspondent inference theory as theoretical frameworks to examine how partisan preference combines with perceptions of unfettered speech and strategic impression management to influence voter judgments of a candidate's authenticity. An online survey of 525 respondents demonstrated that individuals' partisan preferences influenced both judgments of a candidate's authenticity and their perceptions of behaviors signifying authenticity (use of unfettered speech versus strategic impression management). These behavioral signals partially mediated the relation between candidate preferences and authenticity judgments. Moreover, voters, given their partisan preferences, differentially weighted candidates' use of unfettered speech and strategic impression management tactics in their judgments of authenticity. Finally, unfiltered/politically incorrect speech was found to have both positive and negative effects on authenticity judgments. Findings further elucidate the nature of authenticity as perceived in others and identify intermediary variables and boundary conditions that influence those perceptions.