•Perceived negative workplace gossip inhibits targets’ customer service performance by eliciting negative mood.•Trait mindfulness and forgiveness mitigates the effects of negative workplace gossip on customer service performance.•Perceived negative workplace gossip elicits negative mood among targets’ lower in trait mindfulness rather than higher.•Negative workplace gossip inhibits customer service performance among targets’ lower in trait forgiveness rather than higher.•Organizations should make efforts to contribute to the development of mindfulness and forgiveness at work.Organizations should make efforts to contribute to the development of mindfulness and forgiveness at work. This study investigates why and when perceived negative workplace gossip inhibits targets’ in-role performance in the context of service. Relying on affective events theory, we argue that perceived negative workplace gossip inhibits targets’ customer service performance by eliciting negative mood. Furthermore, we argue that this mediating process is moderated by targets’ trait mindfulness and forgiveness. Specifically, we suggest that target employees who are lower (versus higher) in trait mindfulness are more likely to experience negative mood. In turn, the negative mood only inhibits customer service performance among those who have lower (versus higher) tendency to forgive. Results from a multi-wave, multisource field study provide support for our hypotheses, even while controlling for targets’ emotional exhaustion as an alternative pathway. These findings support the affective events perspective to understand negative workplace gossip and provide a more nuanced view on its consequences.