Drawing on the literature on social identity threat, this study examined how threatening ecigarette users' identities in a narrative impacts their perceived behavioral control regarding ecigarette use, and how this effect can be moderated by de-emphasizing the story character's user identity. In an experiment, current e-cigarette users (N = 395) read a conversation between the main character (an e-cigarette user) and their friend. Identity threat was manipulated using negative descriptions of e-cigarette users, and identity emphasis was manipulated through the main character's self-description. Results showed identity threat in a message could influence perceived behavioral control to reduce e-cigarette use through two routes. First, attacking ecigarette users' identity led to perceived threat, which predicted lower perceived behavioral control. Furthermore, character identity emphasis moderated the effect of identity threat: For a character with low identity emphasis, attacking (vs. not attacking) e-cigarette users' identity led to stronger perceived behavioral control; for a character with high identity emphasis, attacking (vs. not attacking) users' identity led to weaker perceived behavioral control. The findings extend the social identity perspective and contribute to health communication research by examining a health behavior-specific social identity and demonstrating the utility of social identity threat as a persuasion strategy.