Background: Increasingly, celebrities are used as spokespeople for nearly all types of marketing. Endorsements can build positive celebrity-brand associations, resulting in favorable brand, product, or issue knowledge. Focus of the Article: This project examines the impact of celebrity influence in social marketing campaigns. Source and receiver characteristics are used to explore how people react to such persuasive messages from celebrities and how those reactions influence behavior. Research Question: Do race (RQ1) and gender (RQ2) of celebrity influence perceptions of (a) credibility, (b) similarity, and (c) heuristic evaluation? How do these factors influence message evaluation (RQ3)? Perceptions of (a) source credibility and (b) similarity as well as (c) heuristic evaluations will increase positive message evaluations (H1). Such positive message evaluations will increase behavioral intentions (H4). Level of (a) perceived source credibility, (b) perceived similarity, and (c) heuristic evaluation of a message is negatively related to message reactance (H2). The level of psychological reactance to a message source is negatively related to behavioral intent related to the message topic (H3). Importance to the Social Marketing Field: The objective of this study is to better understand how characteristics of celebrities, perceptions of the celebrities, and psychological barriers impact intended behavior change attributed to a social marketing message. Because social marketing seeks behavior change as part of an exchange with the targeted audiences, this study contributes a basic understanding of how attributes of the speaker impact social marketing effectiveness. Methods: An experiment was conducted ( N = 798) comparing how persuasive messages from celebrities of different genders and races are perceived. Results: Results indicate that there are significant differences in how persuasive messages from female celebrities are received as compared to messages from male celebrities. Further, race was shown to play a role in feelings of psychological reactance in response to the persuasive messages. Recommendations for Research of Practice: Results suggests marketers should seek out celebrity spokespeople who have the ability to be well-liked by members of the targeted market. The desire to identify with the message source can be a significant enough benefit to inspire behavior change. Having a spokesperson the audience wants to align themselves with is positively correlated with behavioral intentions.