| William Gardner | |
| Birth Date: | c. 1832 |
| Birth Place: | Ireland |
| Placeofburial Label: | Place of burial |
| Rank: | Ship's Cook |
| Battles: | American Civil War Battle of Mobile Bay |
| Awards: | Medal of Honor |
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. He served during the Civil War as a seaman on the . At the Battle of Mobile Bay on August 5, 1864, he "behaved with conspicuous coolness" despite heavy fire. For this action, he was awarded the Medal of Honor four months later, on December 31, 1864. He later obtained the rank of ship's cook.
Gardner's official Medal of Honor citation reads:
As seaman on board the U.S.S. Galena in the engagement at Mobile Bay, 5 August 1864. Serving gallantly during this fierce battle which resulted in the capture of the rebel ram Tennessee and the damaging of Fort Morgan. Gardner behaved with conspicuous coolness under the fire of the enemy.