Harry Ostrer (born May 15, 1951) is an American medical geneticist who investigates the genetic basis of common and rare disorders. In the diagnostic laboratory, he translates the findings of genetic discoveries into tests that can be used to identify people's risks for disease prior to occurrence, or for predicting its outcome once it has occurred. He is also known for his study, writing and lectures on the origins of the Jewish people. He is a professor of Pathology and Genetics at Albert Einstein College of Medicine of Yeshiva University and Director of Genetic and Genomic Testing at Montefiore Medical Center. For the prior 21 years he was Professor of Pediatrics, Pathology and Medicine and Director of the Human Genetics Program at New York University School of Medicine.