The reduction of prison overcrowding, although complex, should be a high priority. This paper reviews factors contributing to that problem, such as criminal justice policies that give excessive weight to punishment or may not have been adequately assessed for impact; lack of alternatives to imprisonment and of sentencing policies and guidelines encouraging the use of non-custodial measures; inefficiency and delays within the justice process; challenges faced by the poor and vulnerable in accessing justice; lack of social reintegration programmes and post-release support to prisoners; and insufficient prison infrastructure and capacity.