1973 (MCMLXXIII) was a common year starting on Monday of the Gregorian calendar, the 1973rd year of the Common Era (CE) and Anno Domini (AD) designations, the 973rd year of the 2nd millennium, the 73rd year of the 20th century, and the 4th year of the 1970s decade.

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.