Crank may refer to:
- Crank conjecture, a term coined by Freeman Dyson to explain congruence patterns in integer partitions.
- Crank, a college slang term for a numerologist or a practitioner of pseudomathematics.
- Crank, in mechanical engineering, a bent portion of an axle, or shaft, or an arm keyed at right angles to the end of a shaft, by which motion is imparted to or received from it
- Crankshaft, the part of a piston engine which translates reciprocating linear piston motion into rotation
- Crankset, the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain, which in turn drives the rear wheel
- Crank (film), a 2006 film starring Jason Statham
- Crank! Records, a record label that released albums by indie bands Mineral, The Gloria Record, and Bright Eyes
- Crank (Hoodoo Gurus album), an album by the Australian rock group Hoodoo Gurus
- Crank, an album by Scottish rock band The Almighty
- Crank, a song by Catherine Wheel off of their album Chrome
- Crank (novel), a book written by Ellen Hopkins.
- Crank, an early 20th century periodical.
- Crank, a radio show host on The Rock Station 93.5 The Beach. "The Night Show With Crank"
- Crank, a disparaging term for a person who holds unorthodox opinions
- Crank calls, a term for false telephone calls made to strangers
- Crank, a slang term for the powdered form of the recreational drugs methamphetamine or amphetamine