Purpose: This article aims to review research measures and findings related to physical environments of assisted living (AL) according to multiple conceptual perspectives--ecological, cultural, and Maslovian hierarchy. Design and Methods: A literature and research review was undertaken with two foci: performance measures for physical environments, and environmental research findings themselves. Results: The research review identified a variety of environmental studies with a broad scope of topics, including post-occupancy design multimethod approaches, homeyness, evolution of AL, services, quality of life as an outcome, aging in place, regulatory influences, and environmental design principles. Most studies were descriptive; few dealt with outcomes linked to the environment, and those that did often focused on dementia settings. Some large scale studies with environmental components suggested that physical designs would affect a resident's ability to age in place within an AL setting. Overall, the environmental research was sparse and often characterized by small samples, lack of longitudinal data, or lack of depth. Implications: The field needs research studies that show how resident and environmental characteristics interact to generate both quality-of-life and functioning outcomes, and it also needs work on measures to permit such studies. I suggest eight specific studies in targeted areas and recommend full post-occupancy evaluation studies to develop in-depth understanding about how a setting works for its users. Research on AL environments is most likely to be meaningful if it anchors itself in the study of housing rather than hospitals, nursing homes, and other health settings.