Sir Gilbert Owen Stephenson KBE, CB, CMG, DL (13 February 1878 – 27 May 1972) was a British Vice-Admiral in the Royal Navy, a pioneer of anti-submarine techniques in World War I, and most famous as an important Naval training commandant during World War II.
Stephenson was born in London on 13 February 1878. His father was a merchant in the Indian trade. Stephenson joined the Navy aged fourteen in 1892 when he began his training in Dartmouth. As a midshipman he was posted to HMS Endymion and HMS Forte. Whilst with the Forte he was involved in the Punitive Expedition of 1897 in Benin. Following promotion to sub-lieutenant on 15 June 1898, he went first to the First Destroyer Flotilla. In February 1900 he was posted to the HMS Ramillies, flagship of the Mediterranean Fleet, and served on the HMS Ocean for the voyage to Malta. The following year he was given his first command, the torpedo boat, TB 90. He was promoted lieutenant in June 1900.