Clarence Lee Swartz (1868–1936) was an American individualist anarchist, whose best-known work, What is Mutualism? (1927) is a book explaining the economic system of mutualism.

Swartz was a friend of Benjamin Tucker and frequent contributor of signed and unsigned editorials to Tucker's newspaper Liberty. In addition, he worked for a series of anarchist newspapers and journals. For instance, he worked in the mechanical department of Liberty beginning in 1891, edited an anarchist journal called Voice of the People and served as assistant editor for Moses Harman's journal Lucifer, the Light-Bearer in 1890.