Thomas O'Hara (1911–1984) was an Irish politician, merchant and auctioneer.
Thomas or Tom O'Hara may also refer to:
- Tom O'Hara (1942–2019), American runner
- Thomas J. O'Hara (born 1949), American Catholic priest
- Tom O'Hara (baseball) (1880–1954), American outfielder in Major League Baseball
- Tom O'Hara, character in The 13th Man
- Tommy O'Hara (1952–2016), Scottish former footballer
- Thomas J. O'Hara C.S.C., Ph.D., American president of King's College, Pennsylvania