Background: Exercise is a safe and beneficial way of improving physical and psychological well-being in postpartum people; yet, postpartum people are less likely to meet the recommended guidelines for physical activity. Identifying the barriers to exercise in the postpartum period may assist health care professionals to better understand how to counsel this population on strategies for exercise. Objective: To synthesize the current literature on barriers to exercise in postpartum people. Study Design: A mixed-methods systematic review. Methods: A systematic literature search was conducted in MEDLINE/PubMed, EMBASE, Scopus, and CINAHL databases of both qualitative and quantitative studies that examined the barriers to exercise among postpartum people. The articles were selected on the basis of predetermined inclusion and exclusion criteria. The Downs and Black Checklist of Methodological Quality was used to assess study quality. Results: Ten studies met the inclusion criteria (7 qualitative and 3 quantitative). Barriers were categorized into the following categories: intrapersonal, interpersonal, sociocultural/demographic, physical environment, and health care environment. The most reported barriers in each category were tiredness and/or lack of sleep (7 out of 10 mentioned), time and/or unpredictable routines/schedule and busy with domestic chores/care/responsibilities (both 8 out of 10 mentioned), lack of support from family, friends, and other mothers (9 out of 10 mentioned), weather (7 out of 10 mentioned), and breastfeeding (3 out of 10 mentioned), respectively. Conclusion: Physical therapists and other health care professionals should be aware of the major reported barriers to exercise among postpartum people, as this will help guide them in providing meaningful education and counseling strategies to increase exercise in this unique population. Further research is needed to capture a more diverse group of postpartum people, as well as considering how policy may affect exercise postpartum.