The social world of prisons is typically described as hierarchical in the prison sociological literature where offence type, displays of (hegemonic) masculinity and involvement in the informal economy impact prisoners’ social standing. Based on fieldwork and interviews (N=181) with men and women in seven different Norwegian prisons, this article describes prisoner cultures where such hierarchies were either absent or of little significance. Rather than pointing out differences in status and standing, the prisoners interviewed tended to insist that they were equal and the same. In order to make sense of this finding, which contrasts dominant accounts in the prison sociological literature, the article engages with scholarship on the role and roots of egalitarianism in Norwegian society. Organizing the discussion around the concepts of ‘egalitarian permeability’, ‘pragmatic egalitarianism’ and ‘social labour’, the article argues that the egalitarian culture of Norwegian (open) prisons are shaped by norms in the wider Norwegian society and the pragmatic choices prisoners make to cope socially in prison everyday life.