Jonas Edward Salk (28 October 1914 – 23 June 1995) was an American medical researcher and virologist, best known for developing the first successful polio vaccine.

Unlike most other researchers, Salk focused on creating an inactivated or "killed" virus vaccine, for safety reasons. The vaccine he developed combines three strains of wild-type poliovirus, inactivated with formalin. The field trial that tested its safety and efficacy in 1954 was one of the largest carried out to date, with vaccine being administered to over 440,000 children. When the trial's success was announced, Salk was hailed as a miracle worker and national hero. A little over two years later, 100 million doses of the vaccine had been distributed throughout the US, with few reported adverse effects. An inactivated vaccine based on the Salk vaccine is the mainstay of polio control in many developed countries.

Salk also researched vaccines against influenza and HIV. In 1960, he founded the Salk Institute for Biological Studies research centre in La Jolla, California.