["Canadian Journal of Administrative Sciences / Revue Canadienne des Sciences de l'Administration, Volume 43, Issue 2, June 2026. ", "\nABSTRACT\nUsing the cognitive appraisal theory of stress and coping, we hypothesized that employees who face supervisor undermining would show a decrease in citizenship behaviours and an increase in negative gossip directed at the supervisor through the development of fear of negative evaluation. We also hypothesized that the relationship between supervisor undermining and fear of negative evaluation would be stronger for those individuals high on rejection sensitivity. We tested our hypotheses using three‐wave time‐lagged data (N = 206 dyads) from independent sources (for outcomes). The findings support the mod‐med relationship, which holds that individuals high in rejection sensitivity in the case of high supervisor undermining might engage in increased negative workplace gossip as well as decreased citizenship behaviours due to fear of negative evaluation. Our study contributes to the OB and emotions literature by suggesting fear of negative evaluation as a pertinent underlying mechanism through which supervisor undermining translates into higher gossip and lower OCBs.\n"]