Mark Siegler (born June 20, 1941) is an American physician who specializes in internal medicine.

He is the Lindy Bergman Distinguished Service Professor of Medicine and Surgery at the University of Chicago.

[2] Siegler has practiced and taught internal medicine at the University of Chicago for more than 50 years.

His textbook, co-authored with Al Jonsen and William Winslade, Clinical Ethics: A Practical Approach to Ethical Decisions in Clinical Medicine, 8th Edition (2015),[4] has been translated into eight languages and is widely used by physicians and health professionals around the world.

[5] Dr. Siegler retired from practicing medicine in 2024 while continuing to be active in the University of Chicago community He has developed a field called Clinical Medical Ethics,[6] the main goal of which is improving the quality of patient care by identifying, analyzing, and contributing to the resolution of ethical problems that arise in the routine practice of clinical medicine.