Rebecca Craighill Lancefield (January 5, 1895 - March 3, 1981) was an American microbiologist. She joined the Rockefeller Institute for Medical Research (now Rockefeller University) in New York in 1918, and was associated with that institute throughout her career. Her bibliography comprises more than 50 publications published over 60 years.

Lancefield is best known for her serological classification of ?-hemolytic