Background: The quality of life (QoL) of nursing home residents is multifaceted and influenced by relationships, health, and activities, as per research in international literature. However, studies exploring QoL predictors considering varying cognitive impairment levels are limited in the French context. This study examined the impact of sociodemographic factors and cognitive impairment on the QoL in Alzheimer’s Disease Nursing Homes (QoL-AD NH) scale scores among French nursing home residents. It further identified predictors through responses to qualitative semi-structured interviews. These elements were integrated and compared to understand more comprehensively the multifaceted determinants influencing residents’ QoL. Methods: This mixed methods study used a cross-sectional convergent design, and quantitative and qualitative studies were carried out simultaneously. Using a generalised linear model and Kruskal–Wallis tests, the quantitative strand (N = 151) measured QoL with the QoL-AD NH scale and examined sociodemographic predictors of QoL. The qualitative strand (N = 78) involved semi-structured interviews with residents across four levels of cognitive functioning (no, mild, moderate, and severe impairment) and explored their QoL determinants through thematic analysis. Both strands were then integrated and analysed. Results: Mild cognitive impairment and depression negatively predicted QoL-AD NH scores. For specific items, residents with mild cognitive impairment had lower “Ability to keep busy daily” and “Current life in general” scores than residents without cognitive impairment. Qualitatively, family relationships were indispensable for QoL across groups, but those with mild cognitive impairment complained about a lack of activities in nursing homes. The analysis identified convergent predictors and enriched our understanding of daily occupation. Theory comparisons revealed assessment limitations in psychological well-being. Conclusions: A mixed approach provided a nuanced understanding of QoL, highlighting vulnerable groups and areas for improving assessment. Combining the results from standardised instruments with semi-structured interviews allowed us to capture a fuller range of experiences. The findings suggest a need to reconsider QoL assessment tools for nursing home residents and policies to address their needs regardless of their cognitive levels. They highlight the value of mixed methods for researching this multifaceted field. © The Author(s) 2024.< Réduire