Gemini 12 was a 1966 crewed spaceflight in NASA's Project Gemini. It was the 10th and final crewed Gemini flight, the 18th crewed American spaceflight, and the 26th spaceflight of all time, including X-15 flights over 100 kilometers (54 nmi). Commanded by Gemini VII veteran James A. Lovell, the flight featured three periods of extravehicular activity (EVA) by rookie Edwin "Buzz" Aldrin, lasting a total of 5 hours and 30 minutes. It also achieved the fifth rendezvous and fourth docking with an Agena target vehicle.

The Titan II GLV or Gemini-Titan II was an American expendable launch system derived from the Titan II missile, which was used to launch twelve Gemini missions for NASA between 1964 and 1966. Two uncrewed launches followed by ten crewed ones were conducted from Launch Complex 19 at the Cape Canaveral Air Force Station, starting with Gemini 1 on April 8, 1964.