jats:p Sex offenders constitute a significant proportion of the prison population – in England and Wales, almost one in six prisoners has been convicted of a sexual offence – and yet they barely feature in sociological studies of prison life. This article is based on research conducted in a medium security English prison which only accommodated sex offenders. It argues that if we are to understand prisoners’ experiences of imprisonment and identity management, it is necessary to explore their horizontal relationships with other prisoners. Prisoners experienced their convictions as an assault on their moral character, resenting attempts to define them as ‘sex offenders’. Following Sykes, we argue that prisoners attempted to form an accepting and equal moral community in order to mitigate the pain of this moral exclusion and to enable the development of a convivial atmosphere. However, these attempts were limited by imprisonment’s structural limitations on trust and prisoners’ imported negative feelings about sex offenders. This suggests that sex offenders may have more complex feelings towards their own moral exclusion than is suggested by their attempts to resist their own stigmatisation. </jats:p>