1971 (MCMLXXI) was a common year starting on Friday of the Gregorian calendar, the 1971st year of the Common Era (CE) and Anno Domini (AD) designations, the 971st year of the 2nd millennium, the 71st year of the 20th century, and the 2nd year of the 1970s decade. The year 1971 had three partial solar eclipses (February 25, July 22 and August 20) and two total lunar eclipses (February 10 and August 6).
The world population increased by 2.1% this year, the highest increase in history.
January 1 – Fifth Street Women's Building Takeover: A coalition of over 100 feminists illegally occupy an abandoned city building in New York City. They establish a women's center, homeless shelter, food co-operative, and lesbian center before being raided by police 13 days later.
January 2 – 1971 Ibrox disaster: During a crush at a football match, 66 people are killed and over 200 injured in Glasgow, Scotland.
January 5 – The first ever One Day International cricket match is played between Australia and England at the Melbourne Cricket Ground.
January 8 – Tupamaros kidnap Geoffrey Jackson, British ambassador to Uruguay, in Montevideo, keeping him captive until September.
January 9 – Uruguayan president Jorge Pacheco Areco demands emergency powers for 90 days due to kidnappings, and receives them the next day.
January 14 – Seventy Brazilian political prisoners are released in Santiago, Chile; Giovanni Enrico Bucher is released January 16.
January 15 – The Aswan High Dam officially opens in Egypt.
Strikes in Poland demand the resignation of Interior Minister Kazimierz Świtała. He resigns January 23 and is replaced by Franciszek Szlachcic.
Ivan Koloff defeats Bruno Sammartino for the WWWF World Heavyweight Championship in wrestling ending a seven and two thirds years reign, the longest in the Championships history.
A South Korean marine kills 6 people in a mass shooting in Kimpo, South Korea.
January 19 – Representatives of 23 western oil companies begin negotiations with OPEC in Tehran to stabilize oil prices; February 14 they sign a treaty with 6 Arab states of the Persian Gulf.
January 24 – The Guinean government sentences to death 92 Guineans who helped Portuguese troops in the failed landing attempts in November 1970; 72 are sentenced to hard labor for life; 58 of the sentenced are hanged the next day.
In Uganda, Idi Amin deposes Milton Obote in a coup, and becomes president.
In Los Angeles, Charles Manson and 3 female "Family" members are found guilty of the 1969 Tate–LaBianca murders.
Himachal Pradesh becomes the 18th Indian state.
Intelsat IV (F2) is launched; it enters commercial service over the Atlantic Ocean March 26.