大洗町（日语：大洗町／おおあらいまち）是茨城县县央东部太平洋岸的一町。

Ōarai(大洗町,Ōarai-machi) is a town located in Higashiibaraki District, Ibaraki Prefecture, in the northern Kantō region of Japan. As of September 2015, the town had an estimated population of 16,823 and a population density of 709 persons per km². Its total area was 23.74 km². The Japan Atomic Energy Agency operates a research center in Ōarai with a number of nuclear research reactors, including the Jōyō and HTTR facilities.