Mariner 10 was an American robotic space probe launched by NASA to fly by the planets Mercury and Venus. It was the first spacecraft to perform flybys of multiple planets.

Mariner 10 was launched approximately two years after Mariner 9 and was the last spacecraft in the Mariner program. (Mariner 11 and 12 were allocated to the Voyager program and redesignated Voyager 1 and Voyager 2.)