Thomas Cocklyn was an 18th-century English pirate, known primarily for his association and partnership with Howell Davis and Oliver La Buze. He was reportedly elected captain "due to his brutality and ignorance" when first sailing from New Providence in 1717.
On April 1, 1719, Cocklyn was a participant in the capture of the West African-bound English slave ship the Bird Galley at the mouth of the Sierra Leone River, after he had been marooned by fellow pirate captain William Moody for attempted mutiny. The three pirate captains celebrated their victory on board the ship for nearly a month before releasing its captain, William Snelgrave, and giving him the Bristol Snow and the remaining cargo left from the pirates' week-long occupation of the ship.
Due to disagreements between the captains, the three parted ways on May 10, 1719. At least one source says Cocklyn died on Madagascar, with captaincy of his ship Victory going to Richard Taylor, who afterwards sailed with Edward England and Jasper Seagar.