Thomas Burr Osborne (August 5, 1859 – January 29, 1929) was a biochemist who, with Lafayette Mendel, independently discovered Vitamin A, though Elmer McCollum and Marguerite Davis were ultimately given credit, as they had submitted their paper first by three weeks. He is known for his work isolating and characterizing seed proteins, and for determining protein nutritional requirements. His career was spent at the Connecticut Agricultural Experiment Station.