Gilliam may refer to:
People:
- Armen Gilliam (1964-2011), American basketball player
- Christian Gilliam, UK Labour Party politician
- David Gilliam, feature film actor
- Herm Gilliam (1946-2005), National Basketball Association player
- Joe Gilliam (1950-2000), American football player
- Jim Gilliam (1928-1978), American baseball player
- John Gilliam (born 1945), former 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
Places:
- Gilliam County, Oregon, on the Columbia River Plateau
- Gilliam, Louisiana, a village
- Gilliam, Missouri, a city
- Gilliam, West Virginia, an unincorporated community
Other:
- USS Gilliam (APA-57), a US Navy attack transport ship
- Gilliam II, a fictional computer system in the manga and anime series Outlaw Star
- Gilliam Candy Company