Loren David Walensky is an American physician-scientist and pediatric oncologist at the Dana–Farber Cancer Institute since 2003 and a professor of pediatrics at the Dana–Farber/Harvard Cancer Center. He researches peptides and oncogenic pathways. In 2013, Walensky became director of the joint MD/PhD program at Harvard Medical School. He is the husband of Rochelle Walensky, director of the Centers for Disease Control and Prevention.