A physician assistant or physician associate (PA) is a healthcare professional licensed to practice medicine with supervision of a licensed physician.[1] A physician assistant is concerned with preventing, maintaining, and treating human illness and injury by providing a broad range of health care services that are traditionally performed by a physician. Physician assistants conduct physical exams, diagnose and treat illnesses, order and interpret tests, counsel on preventive health care, assist in surgery, and write prescriptions.[2]

Physician assistants exercise autonomy in medical decision making as determined by their supervising physician. They are educated in the medical model designed to complement physician training, rather than in the nursing model as nurse practitioners are. Physician assistants are not to be confused with medical assistants, who perform administrative and simple clinical tasks with limited college-level education in hospitals and clinics under the direct supervision of physicians, physician assistants registered nurses, or nurse practitioners.

The profession is represented in the United States by the American Academy of Physician Assistants.