Prior research on tour guides’ influence on tourists’ pro-environmental behavior has largely emphasized informational content (e.g., interpretation) and communication tactics (e.g., humor), while leaving the social-influence role of guides’ emotional displays underexamined, especially with respect to simultaneous affective and cognitive mechanisms. Drawing on Emotions-as-Social-Information (EASI) theory, we develop a dual-path model in which tour guides’ environmental passion affects tourists’ pro-environmental behavior via an affective-reaction pathway (positive emotions) and an inferential pathway (self-protection motivation), with tourists’ self-construal moderating the first-stage effects. Using a seven-day experience sampling (intensive longitudinal) survey (873 day-level observations nested within 159 tourists) and estimating a 1-1-1 multilevel structural equation model with Monte Carlo confidence intervals, we find that guides’ environmental passion predicts tourists’ pro-environmental behavior both directly and indirectly through the two mediators, and these indirect effects are stronger among tourists with a more interdependent self-construal. The study extends EASI theory to guide–tourist interactions and advances tourism sustainability research by clarifying how emotional displays operate as social information in shaping tourists’ daily pro-environmental responses.