McIlwaine is a surname. Notable people with the surname include:
Ellen McIlwaine (1945–2021), American singer-songwriter and musician Garry McIlwaine (born 1944), Australian politician George Arthren McIlwaine (–1930), South African rugby union player Henry Read McIlwaine (1864–1934), American librarian Johnny McIlwaine (1904–1980), Scottish footballer Richard McIlwaine (born 1950), English cricketer Richard McIlwaine (educator) (1835–1913), American theologian and college president Robert McIlwaine (1924–2015), American lawyer and public official
See also McIlwaine House, a historic house in Petersburg, Virginia, United States