1972 (MCMLXXII) was a leap year starting on Saturday of the Gregorian calendar, the 1972nd year of the Common Era (CE) and Anno Domini (AD) designations, the 972nd year of the 2nd millennium, the 72nd year of the 20th century, and the 3rd year of the 1970s decade.

Within the context of Coordinated Universal Time (UTC) it was the longest year ever, as two leap seconds were added during this 366-day year, an event which has not since been repeated. (If its start and end are defined using mean solar time [the legal time scale], its duration was 31622401.141 seconds of Terrestrial Time (or Ephemeris Time), which is slightly shorter than 1908).

In this year, Atari kicks off the first generation of video games with the release of their seminal arcade version of Pong, the first game to achieve commercial success.