This research aims to understand evangelism in the ecosystem of social media-based travel communities (SMTCs). Further, crucial constituents of evangelical behavior in SMTCs setting are studied. A conceptual model depicting an interplay of unique constructs is tested using structural equation models. The findings indicate that in-role and extra-role inspire evangelism and SMTCs engagement. Further, evangelism act as a mediator and have the potential to extend tourism literature. Theoretically, the research sheds newer insights into evangelism and SMTCs' engagement. It is believed that managers may improve their destination's presence and promotion on SMTCs by emphasizing evangelism. Some insights into evangelical behavior are offered through its unique constituents, outcomes, and mediating roles in SMTC settings. The empirical investigations indicate that evangelism inspires engagement with SMTCs. Given this backdrop, the research streamlines, integrate, and unites diverse research streams advancing evangelism in tourism literature.