Rebecca Lancefield, American microbiologist and researcher (b. 1905)
Rebecca Craighill Lancefield (January 5, 1895 – March 3, 1981) was a prominent 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 long and outstanding career. Her bibliography comprises more than 50 publications published over 60 years.

Lancefield is best known for her serological classification of β-hemolytic streptococcal bacteria, Lancefield grouping, which is based on the carbohydrate composition of bacterial antigens found on their cell walls. She is also responsible for the serological typing of Group A Streptococci.