Within sociological literature, including that which analyses systemic changes in the countries of the former Eastern Bloc, denunciation is one of the least studied issues, both empirically and theoretically. In Poland after the political transformation, as well as in other post-communist countries, the problem of dealing with security service and secret police informers and collaborators has not gone away. News media report a rapidly growing number of denunciations directed to various institutions and administrative offices, and legal regulations regarding denunciations have also appeared. In public discourse, denunciation and whistleblowing are increasingly often equated. Encouragement to inform about aberrations, confronted with the consequences that whistleblowers face, shows the legal and social vacuum around the institution of whistleblowing in Poland. This article, in response to questions about the modern social image of denunciation, is based on analysis of in-depth individual interviews conducted during 2015–2017 with children, adults, and administrative officials in three Polish cities. The results show that both children and adults treat denunciation as a form of harming others, though they do differentiate their moral judgments depending on the delator’s intention, but they rarely attribute any motive other than personal gain to whistleblowers’ actions. Finally, the existing administrative acquiescence and institutional support for denunciation are sometimes interpreted in terms of the weakness of democracy, immaturity of civic society, and the legacy of a totalitarian state.