Knowledge hiding has detrimental consequences for organizations. Hence, understanding the antecedents and boundary conditions of knowledge hiding is critical. With our diary study on daily incivility as a situational predictor and the individual difference variables of entitlement and trait self-control as person-related moderators, we attempt to contribute to this understanding. We tested our hypotheses using multilevel path modelling based on data of 75 employees who answered daily surveys on a total of 501 workdays. As hypothesized, incivility was positively related to the deceptive knowledge hiding behaviours of playing dumb and evasive hiding on the between-person level. Incivility was also positively related to supposedly non-deceptive rationalized hiding on the between-person level. On the day level, incivility was not related to knowledge hiding behaviours per se. Rather, day-specific incivility was positively related to playing dumb for employees high on trait entitlement and low on trait self-control. Entitlement and self-control did not moderate the day-level relationship of incivility with evasive hiding nor rationalized hiding. Altogether, our study yields important implications in providing input to theoretical models on knowledge hiding and being valuable for organizations wanting to prevent its occurrence.