W orkplace mistreatment, 1 sometimes labeled abuse, aggression, or harassment, is a prevalent issue in workplaces. It represents interpersonal interactions during which one (or more) social partner initiates negative, counternormative actions or stops positive, normative actions toward another social partner in the workplace (Cortina & Magley, 2003, as cited in Yang et al., 2014. It manifests in many forms among the broad worker population, ranging in intensity, frequency, and focus. The estimated prevalence rate for workplace mistreatment is high. For example, 98% of workers reported experiencing incivility at least once and 50% reported weekly experiences as a target (Porath & Pearson, 2012, as cited in Schilpzand et al., 2016, and about 15% of workers reported experiencing bullying (Nielsen et al., 2010). Workplace mistreatment is consequential for workers and their organizations. Estimates of annual organizational costs attributable to workplace mistreatment have been reported to range from billions for bullying to $14,000 per employee for incivility (Kline & Lewis, 2019; Pearson & Porath, 2009, as cited in Cortina et al., 2017.Workplace mistreatment research has reached a consensus about a longstanding challenge about the conceptual distinction between different forms of mistreatment, which mainly stems from the overlap between commonly used measures of different forms of mistreatment as well as the imprecise operationalization of these mistreatment constructs during measurement (Bowling 1 We omitted some reviews on mistreatment from this chapter, due to space limitation and the fact that they largely overlap with and are less comprehensive than those included here.