Gregg Leonard Semenza (born July 12, 1956) is an American Nobel Laureate who is the professor of pediatrics, radiation oncology, biological chemistry, medicine, and oncology at the Johns Hopkins University School of Medicine.
He serves as the director of the vascular program at the Institute for Cell Engineering.
He is a 2016 recipient of the Albert Lasker Award for Basic Medical Research.
He is known for his discovery of HIF-1, which allows cancer cells to adapt to oxygen-poor environments.
He shared the 2019 Nobel Prize in Physiology or Medicine for "discoveries of how cells sense and adapt to oxygen availability" with William Kaelin Jr.