X-1 may refer to:

Transportation Aircraft Bell X-1, the first aircraft to exceed the speed of sound in controlled level flight

Automobiles Lada X-1, a 1981 Soviet concept MPV McLaren X-1, a 2012 British one-off sports car based on the 12C

Cycles Sinclair X-1, an electrically assisted faired recumbent bicycle Yamaha X-1, a commuter-style motorbike

Watercraft X-1 Submarine, the United States Navy's only midget submarine

Technology Xbox One, a video game console a one-lane PCI Express slot

Arts, entertainment, and media X Minus One, a 1950s American radio show X-Men (film), the first film in the X-Men franchise X-One, monthly magazine produced by Imagine Publishing

Other x −1, the multiplicative inverse of x (another way to denote 1⁄x, one divided by x) Cygnus X-1 and Scorpius X-1, two astronomical x-ray sources M82 X-1, a candidate intermediate-mass black hole detected in January 2006

See also X1 (disambiguation) 1X (disambiguation)