<p>Social media and online environments have been studied in the field of tourism. Most research, however, has focused on businesses, destination-management organizations, and tourists. Local communities are also directly affected by tourism activities. They play a decisive role in supporting or opposing tourism development. Their role has not received enough attention, however. This research focuses on the influence of local online community engagement (LOCE) on residents’ attitudes, their behaviors in supporting tourism development, and the factors of their engagement in these online community fan pages. This study employed online convenience sampling via community Facebook pages and face-to-face judgmental and snowball sampling methods to collect data from residents of Can Tho, Vietnam. Through 552 survey responses obtained from residents of Can Tho City, the results revealed a contrast with previous studies: emotional support emerged as a stronger motivator for residents’ online community engagement than informational or peer support. Subjective norms, perceived behavioral control, and attitudes all exerted significant influence on residents’ support for tourism development. Moreover, LOCE exerted a powerful influence on both attitudes and behavioral intentions to support tourism among residents, despite a discernible gap between their attitudes and intentions. Based on the research findings, several recommendations are proposed.</p>