Well-being is an important outcome for people with dementia. The current study is a secondary analysis of baseline data from an ongoing pragmatic trial. Affect balance, the ratio of positive to negative affect, was used as a measure of well-being, and factors related to it were examined in a sample of 325 nursing home residents. Measures of staff interaction during caregiving, staff knowledge of person-centered approaches for dementia care, staff hours of care, the physical environment, person-centered policies, resident function, and quality of life were obtained using direct observation, staff interview, and medical chart review. The results of the quantile multivariable regression analysis indicated that positive staff interaction and higher resident function were significantly associated with higher affect balance after controlling for other variables. The findings have heuristic value for the development of conceptual frameworks that focus on meaningful outcomes for residents with dementia and future research. [Research in Gerontological Nursing, 13(1), 21-30.]., (Copyright 2019, SLACK Incorporated.)