Sir Michael Foster (8 March 1836 – 29 January 1907) was an English physiologist. He was instrumental in organising the Cambridge Biological School and acted as Secretary of the Royal Society. His main works were a Textbook of Physiology (1876) and Lectures on the History of Physiology during the 16th, 17th and 18th Centuries (1901), which consisted of lectures delivered at the Cooper Medical College, San Francisco, in 1900.

One of his most famous students at Cambridge (Charles Scott Sherrington) went on to win the Nobel Prize in 1932. He was an elected member of Parliament between 1900-1906, representing the University of London and as an avid iris gardener, he was the binomial author of the plant species, Iris Lineata Foster ex Regel

He married in 1864, Georgina Edmonds, daughter of Cyrus Read Edmonds. Following her death in 1869, he remarried in 1872, Margaret Rust, daughter of George Rust, JP, of Huntingdon. He lived at Nine Wells House, Great Shelford in the Gog Magog Hills opposite his friend and fellow physiologist W H Gaskell.