A central tenet of many prominent philosophical and psychological traditions is that personal authenticity facilitates psychological well-being. This idea, however, is at odds with numerous perspectives arguing that it is difficult, if not impossible, to really know one's self, or the true self may not even exist. Moreover, empirical findings suggest that reports of authenticity are often contaminated by positively valenced behavior, further potentially undermining the validity of authenticity measures. Despite these concerns, we argue that subjective feelings of authenticity do uniquely contribute to well-being. Specifically, we argue that the relationship between perceived authenticity and well-being may be understood from a social-cognitive lay theory perspective that we label "true-self-as-guide," that suggests people use these feelings of authenticity as a cue to evaluate whether they are living up to a shared cultural value of what it means to live a good life. We end with a call for future research on the antecedents of perceived authenticity, boundary conditions for the consequences of personal authenticity, and discuss cultural differences in true-self-as-guide lay theories.