William Gardner (born c. 1832, date of death unknown) was a Union Navy sailor in the American Civil War and a recipient of the U.S. military's highest decoration, the Medal of Honor, for his actions at the Battle of Mobile Bay.

Born in about 1832 in Ireland, Gardner immigrated to the United States and was living in New York when he joined the U.S. Navy.

At the Battle of Mobile Bay on August 5, 1864, he "behaved with conspicuous coolness" despite heavy fire.

[3] Gardner's official Medal of Honor citation reads: As seaman on board the U.S.S.

Serving gallantly during this fierce battle which resulted in the capture of the rebel ram Tennessee and the damaging of Fort Morgan.