It is important to direct resources to effective evidence- and value-based counter-radicalization strategies, especially within prisons. With the increasing threat of violence and terror from various violent extremist groups, such as Daesh, the focus on prisons should be intensified. While radicalization within prisons was not a significant problem a decade ago, the new recruitment strategies from e.g. Daesh now pose a new challenge for prisons. This thesis identifies contemporary literature on radicalization, deradicalization, and violent extremism within a prison context. From this seven recurrent themes were identified: overcrowding, religious chaplains, sectioning, risk assessment, monitoring and supervision, rehabilitation programs and education of staff. This was then used to develop an assessment model, which was based on the Canadian Risk-Need-Responsivity model’s three core principles, for evaluating and conducting counterradicalization strategies. The assessment model was then used as a framework for a comparative analysis of the Danish and Swedish Prison and Probation Services’ counter-radicalization strategies within prisons. The results show that both countries adhered to a degree to the assessment model and current literature within the field. The results further reveal that there is a lack of empirical evidence and data on radicalization and counter-radicalization within prisons, and that the data available is somewhat outdated.