A clock is an instrument for measuring time.

Clock, CLOCK, or Clocks may also refer to:

• Clock (American band), a band featuring Vivian Campbell and P.J. Smith
• Clock (British group), an English band primarily led by Stu Allan
• Clocks (American band), a Wichita new wave/pop rock band
• Clocks (British band), a London musical group formed in 2000
• Symphony No. 101 (Haydn) or "The Clock"

• "Clocks" (song), a 2002 song by Coldplay
• "Clock", a 1997 song by Coal Chamber from Coal Chamber
• "Clock", a 1980 song by The Danse Society
• "Clock", a song by Velocity Girl
• "Clocks", a 1974 song by Paul Brett

• Clock (constellation)
• CLOCK (Circadian Locomotor Output Cycles Kaput), a gene related to circadian rhythms
• Clock, the spherical seed head of a mature dandelion

• Clock generator, an electronic oscillator that produces a clock signal for use in synchronizing a circuit's operation.
• Clock (cryptography), a method to facilitate decrypting German Enigma ciphers
• Clock (Apple), a bundled iPhone app
• Windows Clock, a bundled Microsoft Windows app
• Clock, a page replacement algorithm

• Clock (restaurant), a Swedish hamburger restaurant chain
• Clock, an ornamental design on the ankle or side of a sock
• Clock Patience, a card game
• Clock (film), a 2023 science-fiction horror film

• The Clock (disambiguation)
• The Clocks, a work of detective fiction by Agatha Christie
• All pages with titles containing Clock
• CLOCKSS, a closed system using LOCKSS technology
• Clog (disambiguation)
• Cloqué, a cloth