Thriving is a scarcely researched topic in nursing sciences. The present study aimed to explore how older persons experience thriving in care homes as assessed by staff and which demographic characteristics and central interRAI scale factors are associated with thriving. The thriving of 145 residents in four public care homes was measured using the short-form Thriving of Older People Assessment Scale (TOPAS). Both enrolled and registered nurses participated in this study. The data were collected in October to November 2022. Descriptive statistics and logistic regression analyses were performed. Resident thriving was assessed by staff as high. The interRAI scale factor of social engagement showed the strongest association with thriving, followed by gender (female). More attention should be focused on social engagement for care home residents and on the male residents’ thriving. The manuscript was guided by the STROBE checklist.