Tourism social networking sites (SNSs) are websites that provide users with templates for describing their travel experiences and an infrastructure to share such travel posts with a network of like-minded individuals. Tourism SNSs represent an important advertising channel for the tourism industry, as they may assist travelers in selecting destinations and planning vacations on the basis of other travelers’ experiences, which may further stimulate travel and generate income for the tourism industry (Yazdanifard & Yee, 2014). User-generated content (UGC) in the form of travel posts is the core offering and key success factor of tourism SNSs. Travel posts constitute a valuable resource that attracts users to these websites, and they serve as a key data feed into the data mining process that is used to develop travel products on tourism SNSs. However, one problem with tourism SNSs is that their users, especially the new ones, do not publish their travel experiences on these SNSs as often as they do on traditional SNSs, such as Facebook. This may result in a lack of content and, therefore, a loss of potential consumers and, consequently, revenue. Therefore, a study on self-disclosure behavior in writing travel posts may contribute to understanding the reasons why this problem exists and help tourism SNSs improve their service accordingly. The author used multiple theoretical perspectives (social exchange theory and social cognition theory) to develop a comprehensive self-disclosure framework. The framework was tested by using a partial least squares based structural equation modelling (PLS-SEM) approach with data from 443 participants recruited from the two most popular Chinese tourism SNSs: Qyer.com and mafengwo.cn. The findings show that self-disclosure behavior on tourism SNSs was significantly affected by self-benefit, positive feedback from other users, social benefits, rewards, tourism SNSs’ security mechanism, and ease of use. However, habit and motive did not have a statistically significant effect on self-disclosure behavior. Moreover, self-disclosure behavior positively affected electronic word of mouth (EWOM) relating to the tourism SNSs. Finally, the findings have theoretical and practical implications, and the thesis ends with a discussion of the limitations of this study and suggestions for future research.