Environmental factors are at the heart of many performance problems after traumatic brain injury (TBI). This vulnerability negatively affects the ability of the patient to generalize treatment gains made in an artificial clinic environment to more naturalistic settings like home and work. It also impacts the rehabilitation professional's ability to predict the performance of a patient in these and other real world settings. Rehabilitation efforts that make patient environmental interactions part of the treatment plan will increase generalization and predictability. Rehabilitation efforts should include data-based definitions of the environment(s) within which each individual can best function. Also important is a focus on the tasks that he or she can perform within those environment(s). When a discharge goal is to return to work, rehabilitation efforts must include: identifying job settings where enabling environments can be established and providing ongoing support to the individual in the job situation should the environment change. More research is needed on the use and benefits of an environmentally focused treatment model.