This study examines the effect of social media influencers on encouraging sustainable tourism practices amongst social media customers of Jordan. Grounded in the Theory of Planned Behavior (TPB), the study incorporates the digital influencer properties, content quality, source credibility, and influencer engagement as antecedents of the tourists’ attitude toward sustainable tourism and their intentions to engage in it. A quantitative method was applied, and data were collected from 250 current social media users following travel influencers. A Partial Least Squares Structural Equation Modelling (PLS-SEM) was applied to test the proposed relationships. The study findings showed that content quality and perceived source credibility have significant and positive and positive impacts on both attitude and behavioral intentions, while influencer engagement has a small but negative effect. Attitude towards sustainable tourism was the strongest predictor of behavioral intention, as is in line with the central role of attitude in TPB. The outcomes provide theoretical contributions by transplanting TPB to a digital marketing context and supply useful implications for brand marketing, tourism administrators, and policymakers wanting to mobilize sustainable tourist behavior via digital effect styles.