Gemini 5 was a 1965 crewed spaceflight in NASA's Project Gemini. It was the third crewed Gemini flight, the eleventh crewed American spaceflight, and the nineteenth human spaceflight of all time. It was also the first time an American crewed space mission held the world record for duration, set on August 26, 1965, by breaking the Soviet Union's previous record set by Vostok 5 in 1963. This record might have been one day longer; however, Gemini V was cut short, due to the approach of Hurricane Betsy.

Project Gemini was the second United States human spaceflight program to fly. Conducted after the first American manned space program, Project Mercury, while the Apollo program was still in early development, Gemini was conceived in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual astronauts flew low Earth orbit (LEO) missions during 1965 and 1966.