Gilliam is a surname. Notable people with the surname include:
Armen Gilliam (1964–2011), American basketball player
Christian Gilliam, philosopher
Cornelius Gilliam, Oregon pioneer
David Gilliam, feature film actor
Herm Gilliam (1946–2005), National Basketball Association player
James Frank Gilliam (1915–1990), American historian of ancient Rome
Jim Gilliam (1928–1978), American baseball player
John Gilliam (born 1945), former American football player
Joe Gilliam (1950–2000), American football player
Michelle Phillips (born Holly Michelle Gilliam in 1944), American singer in the group The Mamas & the Papas, and actress
Robert B. Gilliam (1805–1870), American politician and judge
Robert Gilliam, birth name of Welsh guitarist Tich Gwilym (1951-2005)
Sam Gilliam (born 1933), African American artist
Terry Gilliam (born 1940), film director and member of the Monty Python comedy troupe
