Timothy Sullivan ("Big Tim" Sullivan) (1862–1913) was a New York politician who controlled Manhattan's Bowery and Lower East Side districts.
Tim or Timothy Sullivan may also refer to:
- Timothy Sullivan (composer) (born 1954), Canadian composer
- Timothy Daniel Sullivan (1827–1914), journalist, nationalist politician, poet, and writer of the Irish national hymn "God Save Ireland"
- Timothy J. Sullivan (born 1944), Twenty-fifth President of the College of William and Mary in Williamsburg, Virginia
- Timothy S. Sullivan, Rear Admiral of the United States Coast Guard
- Tim J. Sullivan, Deputy Sports Editor of the New York Post
- Timothy Sullivan (Irish judge) (1874–1949), Chief Justice of Ireland 1936–46
- Timothy Sullivan (Medal of Honor) (1835–1910), American Civil War sailor and Medal of Honor recipient
- Tim Sullivan (athlete) (born 1975), Australian Paralympic track and field athlete
- Tim Sullivan (writer) (born 1948), American science fiction author
- Tim Sullivan (director) (born 1964), American film director and screenwriter
- Tim Sullivan (British filmmaker) (born 1958), British film director and screenwriter
- Ted Sullivan (baseball) (1851–1929), real name Timothy Sullivan
- Tim Sullivan (sports columnist), American sports columnist