Clarence Frederick Leary (11 January 1894 – 20 July 1918) was an officer in the United States Navy during World War I. Leary was born in Fowey, England, and soon immigrated with his family to the United States. After the US entered World War I, on 12 June 1918 he was commissioned as a lieutenant in the Naval Reserve. He was later appointed the Executive Officer of the cargo ship USS Charlton Hall, with Lieutenant Commander J. L. Evans, USNRF, in command of the ship. Lieutenant Clarence F. Leary was posthumously awarded the Navy Cross for his self-sacrificing valor.