BACKGROUND AND AIMS: There are limited data regarding associations between gaming disorder and physical activity (PA). The present study investigated the direct association between these two variables and assessed the potentially mediating roles of PA avoidance and two types of weight stigma (i.e., internalized weight stigma and perceived weight stigma) in the association. METHODS: An online cross-sectional survey that assessed PA avoidance, two types of weight stigma, and PA level was completed in late 2023 by 884 Taiwanese young adults aged between 20 and 40 years (63.9% females). Multinomial logistic regression and structural equation modeling (SEM) were used to assess the associations between variables and perform the mediation analysis. RESULTS: Cognitive behavioral symptoms and negative consequences related to gaming disorder were more common among participants with lower PA than those with moderate to high PA. Individuals at risk of gaming disorder exhibited higher level of PA avoidance, internalized weight stigma, and perceived weight stigma. The SEM found a direct association between gaming disorder and PA, which was negatively mediated by PA avoidance. However, this direct effect was not present when the association was negatively mediated by serial mediations of weight stigma and PA avoidance. DISCUSSION AND CONCLUSIONS: Higher gaming disorder was associated with higher levels of PA, but this association may not be present when taking into account the mediation effect of weight stigma and PA avoidance. The findings suggest complex relationships and further research is needed to examine individual differences and relationships among clinical groups.