Research on subjective well-being (SWB; i.e., happiness) relies heavily on self-report methodologies. This dissertation explores the influence of self-enhancement, or the tendency to evaluate oneself in an unrealistically positive way, on self-reported judgments of happiness and life satisfaction. Further, it examines how accounting for self-enhancement can influence--and in some ways, even reverse--our understanding of happiness differences between political conservatives and liberals. Three studies in Chapter 2 demonstrate a distorting effect of self-enhancement on self-reports of SWB. It is shown that both dispositional levels of self-enhancement and experimentally manipulated self-enhancement motivation lead to a tendency to report SWB at unrealistically favorable levels in social comparative judgment tasks, as well as on established scales of SWB. Chapter 3 of the dissertation examines group-level differences in self-enhancement between political conservatives and political liberals. Meta-analyses of eight measures of self-enhancement reveal significant positive relationships with general, economic, social, and moral dimensions of political conservatism. Chapter 4 examines whether liberal-conservative differences in self-enhancement explain why conservatives typically report greater SWB than liberals. Chapter 4 finds that conservatives' stronger tendency to engage in self-enhancement fully mediates the ideology--SWB relationship. Three additional studies assess happiness-related behaviors among liberals and conservatives using large archives of text from the U.S. Congressional Record and Twitter, along with photographs from the U.S. Congressional Pictorial Directory and LinkedIn. Chapter 4 shows that liberals use more frequent positive emotional language and less frequent negative emotional language, and also that liberals smile more intensely and genuinely than conservatives. These findings support the hypothesis that conservatives' reports of SWB are attributable to a self-enhancing style of self-report. In the Epilogue, practical implications of the research are discussed, specifically regarding the use of self-report methods to assess and compare group-level differences in SWB for use in public policy decision making. Theoretical implications of the research are also discussed. In particular, the nature of the long-debated relationship between self-enhancement and well-being is discussed, as are recommendations for measuring SWB, along with potential implications for re-conceptualizing multiple (i.e., defensive) manifestations of happiness.