Prison staff and residents with sexual convictions, from two UK prisons, were interviewed to explore their understanding and experiences of dementia. The aim was to explore understanding and experiences of dementia in response to Governor-identified needs in the prisons. Semi-structured interviews were conducted with 13 prisoners and 17 prison staff across both prisons, all of whom had direct prisoner contact. Transcripts of the interviews were created and thematic analysis was carried out. Four superordinate themes emerged from the data. The first theme, ‘Balancing act’, explored the way that individuals with dementia should be encouraged to be independent whilst still meeting their need for support in some tasks and areas of functioning. The second theme, ‘Challenges and confusion’, explored the way that dementia symptoms might be masked in prison settings, how they can be misinterpreted and the impact and understanding of inappropriate behaviour in a prison for those with sexual convictions. ‘What works and what doesn’t’ in a prison setting formed the basis of the third theme, with the final theme, ‘Who to tell?’ exploring the transfer of information and the sources of support available in the prisons. Practical suggestions for caring for individuals with dementia in prison are made.