Micaiah John Muller Hill FRS (1856–1929) was an English mathematician, known for Hill's spherical vortex and Hill's tetrahedra. He was born on 22 February 1856 in Bengal, India, the son of Revd. Samuel John Hill (1825–1881) and Leonora Josephina Muller (1833–1917). In 1894 Hill was elected FRS. In 1926 and 1927 he served as president of the Mathematical Association. Hill was one of the people to whom C. L. T. Griffith sent, in 1912, some of Ramanujan's work.