Dr. John Markowitz is an American physician, a Professor of Clinical Psychiatry at the Columbia University College of Physicians & Surgeons and a Psychiatric Researcher at the New York State Psychiatric Institute.

He received his undergraduate and medical degrees from Columbia University and did his psychiatric residency at the Payne Whitney Clinic, New York Hospital-Cornell Medical Center. He subsequently joined the faculty at Cornell, where he trained in IPT with the late Gerald L. Klerman, M.D., the co-developer of IPT.

Dr. Markowitz conducts comparative treatment research, studying the benefits of psychotherapies and medications for people with depression, Post Traumatic Stress Disorder (PTSD), and personality disorders. He has expertise in delivering many of these treatments, particularly psychotherapies such as Interpersonal Psychotherapy (IPT) for depression and PTSD.