Julius H. Comroe, Jr. (March 13, 1911 – July 31, 1984) was a surgeon, medical researcher, author and educator, described by The New York Times as an "award-winning expert on the functions and physiology of the human heart and lungs". His work contributed to advances in respiratory physiology, cardiology, heart and vascular surgery, and the treatment of pulmonary disease, hypertension and high blood pressure.