Prosocial behavior plays an important role in promoting a sustainable and inclusive society. However, the academic investigations regarding tourist prosocial behavior have been limited and ambiguous. This research aimed to develop the measurement instruments to measure tourist prosocial behavior. Through a mixed methods approach across four different studies, this research established a 27-item, sixdimensional measurement scale of tourist prosocial behavior. Using the proposed scale, this study examined the relationship between social exclusion, tourist prosocial behavior, and tourist well-being to assess the nomological validity. This research extends the current knowledge of prosocial behaviors by defining tourist prosocial behavior and examining its dimensionality. It also provides practical insights related to destination marketing and interventions to promote tourist prosocial behavior.Keywords: tourist prosocial behavior, social exclusion, tourist well-being, scale development tourism market is still fierce and the controversy between tourist and host is by no means a rarity.Rooted in the field of social psychology, prosocial behavior has attracted extensive attention from researchers with different theoretical perspectives (e.g., the evolutionary perspective, cognitive perspective, and biological affective perspective) (Wispe, 1972;Xiao, Zheng, & Chen, 2014). These perspectives have yielded valuable and provocative results. However, progress has been hindered by its conceptual vagueness and disagreement about measurement, with different scholars using the same term for various situations or employing different terms for the identical situation (Xiao et al., 2014). So, while prosocial behavior has clearly captured the curiosity of scholars from the field of tourism (Liu & Tsaur, 2014;Coghlan, 2015), it also faces the challenge of unclear definitions and lack of effective measurement tools.Research on prosocial behavior in the tourism context has mainly focused on residents' prosocial behavior toward tourists, while studies on tourist behavior is limited (Tung, 2019;Wu, Wu, Li, & Tong, 2022). Moreover, the differences between tourist prosocial behavior and some similar concepts -such as tourist citizenship behavior, proenvironment behavior, helping behavior, and altruistic behavior -have not been clearly specified (Assiouras et al., 2019;Holmes, Dodds, & Frochot, 2021;Chen, Bai, & Luo, 2021). These analyses of tourist behavior have mainly focused on specific behaviors, and the measures are often uncorrelated. Consequently, the literature lacks a comprehensive discussion on tourist prosocial behavior. It becomes imperative to delve deeper into the subject, exploring its unique logical structure and connotations to obtain a more comprehensive perspective. Considering the growing consensus that understanding prosocial behavior requires a multidimensional approach, this study develops a multi-dimensional Tourist Prosocial Behavior Scale (TPBS) to promote a clearer understanding of tourist prosocial acts.