The concept of denial has a distinguished pedigree in criminology. This chapter describes how it has been used to understand crimes ranging from minor youthful delinquencies to major genocides. Drawing on the work of Sykes and Matza and Matza, the chapter begins by describing how ‘techniques of neutralization’ – the accounts and stories that structure various denials – are said to operate to release people from moral binds and enable transgression. It then turns to the concept of ‘pluralistic ignorance’ – where members of groups inadvertently reinforce one another’s misunderstanding of a situation – showing how it facilitates the commission of crimes, and illustrating its pivotal role in patterning public reaction to crime and injury. Ignorance and denial play major parts in the social reaction to crime, and this, therefore, can have deleterious consequences. The theatres of acknowledgement for state crimes are international courts, tribunals, and various transitional justice systems and forms of memorialization.