Recently, consumers have been searching for tourism information and sharing tourism content using various forms of social media. They are also forming relationships with others by exchanging their opinions regarding tourism information. Accordingly, research on social media has been conducted in the tourism field, primarily focusing on information acceptance and attitude formation. However, research that focuses on tourism information characteristics and attempts to explain users' tourism information sharing intention formation through cognitive responses to such information, affective responses from relationships with other users on social media, and the influence of other users remains limited. Therefore, this study sought to examine whether information quality and source credibility of tourism information on social media affect people's tourism information sharing intention through perceived usefulness, social capital, and social norms, by considering tourism information on social media as persuasive messages and adopting an integrated perspective combining the Elaboration Likelihood Model, social influence theory, and social capital theory. To this end, an online survey was conducted, and empirical verification was performed using a total of 700 valid questionnaires. The results showed that the credibility of tourism information sources on social media had a significant effect on perceived usefulness, social capital, and social influence. Furthermore, perceived usefulness and social influence were confirmed as factors that positively affect social capital. Finally, perceived usefulness, social capital, and social influence were found to be important variables in the formation of tourism information sharing intention. However, tourism information quality did not have a significant effect on perceived usefulness. This study has theoretical implications in that it empirically analyzed individuals' tourism information sharing intention on social media by integrating the Elaboration Likelihood Model, social influence theory, and social capital theory. Additionally, the results of this study revealed that source credibility is more important than information quality on social media, and that the influence of other users is also significant. Accordingly, social media companies should faithfully provide information search functions, and tourism-related marketers should also pay attention to building relationships with users.