Doctor of Osteopathic Medicine (DO or D.O.; referred to in Australia as DO USA) is a medical degree conferred by the 42 osteopathic medical schools in the United States. DO and Doctor of Medicine (MD) degrees are equivalent: a DO graduate may become licensed as a physician or surgeon and thus have full medical and surgical practicing rights in all 50 US states. As of 2023, there were 186,871 osteopathic physicians and medical students in DO programs across the United States. Osteopathic medicine (as defined and regulated in the United States) emerged historically from the quasi-medical practice of osteopathy, but has become a distinct and proper medical profession.

As of 2024, 28% of all U.S. medical students were DO students, while 11% of all U.S. physicians were osteopathic physicians. The curricula at DO-granting medical schools are equivalent to those at MD-granting medical schools, which focus the first two years on the biomedical and clinical sciences, then two years on core clinical training in the clinical specialties.

One notable difference between DO and MD training is that DOs spend an additional 300–500 hours to study pseudoscientific hands-on manipulation of the human musculoskeletal system (osteopathic manipulative technique) alongside conventional evidence-based medicine and surgery like their MD peers.

Upon completing medical school, a DO graduate can enter an internship or residency training program, which may be followed by fellowship training. DO graduates attend the same graduate medical education programs as their MD counterparts.