Thomas A. Gardiner (August 2, 1832 New York City – May 2, 1881 Brooklyn, Kings County, New York) was an American politician from New York.
He was the son of George W. Gardiner (d. 1852), an Irish-born merchant. The family removed to Brooklyn in 1840.
As a Democrat, he was a member of the New York State Assembly (Kings Co., 4th D.) in 1859; a member of the New York State Senate (2nd D.) in 1860 and 1861; and Treasurer of Kings County from 1863 to 1880.
He died at his residence, at 49 Portland Ave., Brooklyn, of pulmonary hemorrhage.