The purpose of this dissertation research was to understand the decision-making process that well older adults use when deciding whether to make a home modification. The researcher also sought to understand the views of well older adults concerning the use of home modification to prevent injury and declines in occupational performance. The researcher used the Person-Environment-Occupation (PEO) model (Law et al., 1996) from occupational therapy and occupational science as the orienting framework. A qualitative grounded theory approach based on that proposed by Strauss and Corbin (1998) was used to structure data collection and analysis. Participants were obtained using purposive and theoretical sampling and were interviewed by the researcher. The 19 participants in this study ranged in age from 65 to 89. Findings from this study include a model of the decision-making process that well older adults used to plan for their futures related to home setting and modification and also a substantive grounded theory. The Theory of Home Modification Decision-Making: Well Older Adults is proposed and explained. Central to the theory are two decision-making processes, including the conditions that influence the decisions. These findings and the theory are discussed relative to the PEO model and existing occupational therapy and gerontology literature. The information gained from this study is beneficial to occupational therapists and Certified Aging-in-Place Specialists to improve and expand their services to the well older adult population.