The present study explores the “social oil” function of humility at the workgroup level. Specifically, we examine collective humility, which reflects observable and consistent patterns of behavioral regularities exhibited by teams, as an explanation for linking group humility composition to reduced group experienced incivility. Drawing on the collective personality perspective, we hypothesize that teams with a high mean on members’ humility could facilitate collective humility, in turn reducing group experienced incivility. We further propose two contingency factors that influence this proposed mediation pathway: (1) high group humility diversity could neutralize the positive association between group humility mean and collective humility and (2) an elevated differentiation of group incivility exposure will weaken the negative relationship between collective humility and group experienced incivility. Relying on a time-lagged, multisourced survey from 83 professional work teams, we tested this proposed moderated mediation model and found support for our hypotheses. Our findings have implications for team building and team management regarding personnel selection for humility, reducing the diversity of humility within teams, and explicitly valuing expressed humility in workgroups. (PsycInfo Database Record (c) 2021 APA, all rights reserved)