Background: Despite the evidence to support exercise as an effective management strategy for patients with cancer-related fatigue (CRF), many of the general cancer population are sedentary. Objective: The aim of this study was to explore the barriers to and facilitators ofexercise among a mixed sample of patients with CRF. Design: An exploratory, descriptive, qualitative design was used. Methods: Purposive sampling methods were used to recruit patients with CRFwho were representative of the cancer trajectory, that is, survivors of cancer and patients in palliative care who were recently diagnosed and undergoing treatment. Focus group discussions were transcribed verbatim and analyzed using a grounded theory approach. Lower-level concepts were identified and ordered into subcategories. Related subcategories then were grouped to form the main categories, which were linked to the core category. Results: Five focus groups were conducted with 26 participants. Within the core category of the cancer rehabilitation journey were 3 main categories: (1) exercise barriers, (2) exercise facilitators, and (3) motivators of exercise. Exercise barriers were mainly related to treatment side effects, particularly fatigue. Fatigue was associated with additional barriers such as physical deconditioning, social isolation, and the difficulty of making exercise a routine. Environmental factors and the timing of exercise initiation also were barriers. Exercise facilitators included an exercise program being group-based, supervised, individually tailored, and gradually progressed. Exercise motivators were related to perceived exercise benefits. Conclusions: Individuals with CRF have numerous barriers to exercise, both during and following treatment. The exercise facilitators identified in this study provide solutions to these barriers and may assist with the uptake and maintenance of exercise programs. These findings will aid physical therapists in designing appropriate exercise programs for patients with CRF.