Katherine S. Ralls (born 1939) is an American zoologist and conservationist who is a senior research biologist at the Smithsonian Institution. She studies the behavior and genetics of endangered mammals. Two mammals that she has studied extensively are the sea otter and the San Joaquin kit fox.
She obtained a BA in Biology from Stanford in 1960, an MS in Biology from Radcliffe College in 1962 and a PhD in Biology from Harvard in 1965. In 2005 she was granted an honorary fellowship in the Zoological Society of London.
- Mihelich, Peggy. "Katherine Ralls, a pioneer in wildlife preservation". AAAS. Retrieved 26 January 2013.