Weight stigma and discrimination have become a topic of global importance. Indeed, this is underscored by the evidenced impact of these experiences on physical and mental health and health related behaviors such as avoidance of healthcare environments and reduced healthcare seeking behaviors (e.g., Puhl and Suh, 2015). Extant research (e.g., Latner et al., 2013) has focused on weight bias internalization (WBI) and the associated implication, which include reduced quality of life and maladaptive behavioral response. WBI refers to “internalization of negative weight stereotypes and subsequent self-disparagement” (Pearl and Puhl, 2018, p. 1141). Although people across the weight spectrum experience WBI, it is most commonly experienced by people with a higher weight status. The commonality of weight stigma and discrimination experiences for people with overweight and obesity means that internalization of weight bias is likely, and, with the associated impacts on health and health behaviors, is an important consideration across society. In editing this Research Topic, we have sought to present emerging empirical and theoretical contributions that advance current understanding of the impact of WBI, specifically on health and health behavior and the underlying mechanisms that lead to WBI. Thus, we present a range of research contributions from across the world, which hold important implications for policymakers and healthcare practitioners.