Aims: The aims of this study were to compare quality of life (QOL) in people with young-onset Alzheimer’s (AD) and frontotemporal (FTD) dementia, explore variables associated with QOL, and compare QOL in young-onset dementia (YOD) and late-onset dementia (LOD). Methods: Cross-sectional data from a Nordic multicenter study of 50 community-dwelling participants with AD and 38 with FTD were included. A comparison group consisted of 100 people with LOD. QOL was measured using self-reported Euro-QOL 5-Dimension and the proxy version of Quality of Life in Alzheimer’s Disease (QOL-AD) questionnaire. Neuropsychiatric symptoms and needs were assessed using the Cornell Scale for Depression in Dementia (CSDD), Neuropsychiatric Inventory (NPI), and Camberwell Assessment of Needs in the Elderly. Multiple linear regression and multilevel modeling was used to determine variables associated with QOL. Results: We found no differences between the two YOD groups in QOL. The variables associated with QOL were scores on the CSDD, NPI, and unmet needs. The proxy QOL-AD score in YOD was significantly higher compared to LOD (median 36.0 [IQR 10.0] vs. 33.0 [IQR 9.0]). Conclusion: The QOL in Nordic people with YOD was better compared to people with LOD. Our results show depressive symptoms to be associated with QOL irrespective of age and diagnosis.