Gardiner is an unincorporated community and census-designated place in Douglas County, Oregon, United States, across the Umpqua River from Reedsport. It is located on U.S. Route 101. As of the 2010 census, it had a population of 248. Gardiner is named for a Boston merchant whose ship, the Bostonian, shipwrecked at the mouth of the Umpqua on October 1, 1850.