Workplace incivility has received increasing attention from hospitality and tourism scholars because of its implications for service outcomes. In the present study, we focused on supervisor incivility as a factor that negatively affects flight attendants' service performance. The objective of the present study was to examine how supervisor incivility affects flight attendants' service performance and when this relationship can be buffered. We proposed the indirect effect of supervisor incivility on service performance through job insecurity and the moderating effect of coworker emotional and instrumental support on this relationship. To test these effects, we administered two-wave surveys to 222 South Korean flight attendants. Results indicated the significant mediating effect of job insecurity on the relationship between supervisor incivility and service performance. Of the two types of coworker support, only emotional support significantly lessened the positive relationship between supervisor incivility and job insecurity. Coworker emotional support further mitigated the indirect effect of supervisor incivility on service performance through job insecurity. These findings have implications for theory and practice.