The broad topic of this doctoral dissertation is behavior and behavior change related to environmental sustainability and health, with a focus on the role of design and the physical environment. Two studies consider behavior at two different stages in a product's lifecycle: the use phase and a product's end-of-life (product or resource recovery). A third study, with an emphasis on behavior in context, explores pro-environmental behavior in early adulthood. First, Creating a New Behavior to Address a New Problem: The Case of Safe Drug Disposal (Chapter 2) addresses improper disposal or stockpiling of unused, expired, or otherwise unwanted medication and safe disposal behavior, such as returning unwanted medications through a pharmaceutical take-back program. A three-part study, including a cross-sectional survey of drug take-back event participants, a cross-sectional survey of a random sample of New York State residents, and an experimental survey, explored disposal behavior and perceptions of various disposal methods. Findings provide insight into important factors influencing out-of-home disposal behavior, including convenience of and familiarity with disposal locations. The second study, Lab Fume Hood Closure: A Behavior Change Experiment (Chapter 3), looks at behavior associated with the use of an energy-intensive piece of laboratory safety equipment. The study included an experiment to test whether the addition of a closure signifier (a sticker) and the provision of comparative feedback would decrease the number of times fume hoods were left. Findings suggest there are opportunities to improve the design of fume hoods to indicate proper closure behavior, as well as opportunities to use automated building data to provide laboratory workers with feedback to promote energy conservation. Finally, Development of the Environmental Behavior Scale for Young Adults (EBS-YA) (Chapter 4) describes the process for creating a new, valid and reliable pro-environmental behavior scale relevant to young adults who have limited control over their environment and do not own a home. The resulting 32-item scale, which poses questions for specific physical contexts, can be used to evaluate interventions (with pre and post measures) and can be used to facilitate longitudinal research that assesses pro-environmental behavior over the lifespan.