Incivility at work—low intensity deviant behaviors with an ambiguous intent to harm—has been on the rise, yielding negative consequences for employees’ well-being and companies’ bottom-lines. Although examinations of incivility have gained momentum in organizational research, theory and empirical tests involving dynamic, within-person processes associated with this negative interpersonal behavior are limited. Drawing from ego depletion theory, we test how experiencing incivility precipitates instigating incivility toward others at work via reduced self-control. Using an experience sampling design across 2 work weeks, we found that experiencing incivility earlier in the day reduced one’s levels of self-control (captured via a performance-based measure of self-control), which in turn resulted in increased instigated incivility later in the day. Moreover, organizational politics—a stable, environmental factor—strengthened the relation between experienced incivility and reduced self-control, whereas construal level—a stable, personal factor—weakened the relation between reduced self-control and instigated incivility. Combined, our results yield multiple theoretical, empirical, and practical implications for the study of incivility at work.