Gemini 12 (officially Gemini XII) was a 1966 crewed spaceflight in NASA's Project Gemini. It was the 10th and final crewed Gemini flight (Gemini 1 and Gemini 2 were uncrewed missions), 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.
Gemini XII marked a successful conclusion of the Gemini program, achieving the last of its goals by successfully demonstrating that astronauts can effectively work outside of spacecraft. This was instrumental in paving the way for the Apollo program to achieve its goal of landing a man on the Moon by the end of the 1960s.