Objectives: To develop understanding of the lived experiences of children of people living with young onset dementia, defined as individuals both under and over the age of 18 years whose parent was diagnosed with dementia before the age of 65 years. Method: A critical appraisal and thematic synthesis of the available qualitative literature regarding the lived experience of individuals whose parent has a diagnosis of young onset dementia. A three-stage approach for conducing thematic synthesis was followed. Results: 15 articles were included in the review. Four analytical themes and 11 subthemes were found. The analytical themes were ‘making sense of dementia’, ‘impact of dementia’, ‘coping’ and ‘support’. Conclusions: The experiences of those affected by parental young onset dementia vary widely. There is a lack of knowledge and understanding of young onset dementia by professionals and the public, and a scarcity of appropriate support. This has clinical implications for professionals working with families affected by young onset dementia, in particular with regards to service design and delivery.