Hazing, or bastardisation, has been the subject of repeated scandal in the Australian Defence Force (ADF) for at least 40 years. At its most serious, as documented in the 2011 Piper Report, hazing is clearly criminal behaviour. This article uses the techniques of criminology to explore hazing as a group social practice in the ADF, and considers whether the response of the ADF to hazing can be characterised as collective denial.