The experiences of persons convicted or charged with sex‐related offences are informed by trends in how the sex offender population in society is defined and understood. I draw on data from in‐depth semi‐structured interviews with 100 Canadian provincial correctional officers to explore the harms tied to the framing of sex offenders in prison, including those embedded in institutional structures. I conceptualise how correctional officers understand sex offenders and how the structures in place to ‘protect’ those labelled as sex offenders are, unintentionally, harmful in their own right. I argue that officers rely on evolving strategies of risk mitigation that they must understand, develop, and learn in the prison context. Emphasis is placed on possible policy or needs that may assist in recognising how ‘protective custody’ may simply be lip service to further stigmatise an already marginalised population.