| 37201 | April 1 | Event | 1969 – The Hawker Siddeley Harrier enters service with the Royal Air Force. |
| 37202 | April 1 | Event | 1970 – President Richard Nixon signs the Public Health Cigarette Smoking Act into law, requiring the Surgeon General's warnings on tobacco products and banning cigarette advertising on television and radio in the United States, starting on January 1, 1971 |
| 37203 | April 1 | Event | 1971 – Bangladesh Liberation War: The Pakistan Army massacre over 1,000 people in Keraniganj Upazila, Bangladesh. |
| 37204 | April 1 | Event | 1973 – Project Tiger, a tiger conservation project, is launched in the Jim Corbett National Park, India. |
| 37205 | April 1 | Event | 1974 – The metropolitan and non-metropolitan counties of England come into being. |
| 37206 | April 1 | Event | 1976 – Apple Inc. is formed by Steve Jobs, Steve Wozniak, and Ronald Wayne. |
| 37207 | April 1 | Event | 1976 – Conrail takes over operations from six bankrupt railroads in the Northeastern U.S.. |
| 37208 | April 1 | Event | 1976 – The Jovian–Plutonian gravitational effect, soon revealed as an April Fools' Day hoax, is first reported by British astronomer Patrick Moore. |
| 37209 | April 1 | Event | 1978 – The Philippine College of Commerce, through a presidential decree, becomes the Polytechnic University of the Philippines. |
| 37210 | April 1 | Event | 1979 – Iran becomes an Islamic republic by a 99% vote, officially overthrowing the Shah. |
| 37211 | April 1 | Event | 1986 – Sector Kanda: Communist Party of Nepal (Mashal) cadres attacks a number of police stations in Kathmandu, seeking to incite a popular rebellion. |
| 37212 | April 1 | Event | 1989 – Margaret Thatcher's new local government tax, the Community Charge (commonly known as the "poll tax"), is introduced in Scotland. |
| 37213 | April 1 | Event | 1997 – Comet Hale–Bopp is seen passing at perihelion. |
| 37214 | April 1 | Event | 1999 – Nunavut is established as a Canadian territory carved out of the eastern part of the Northwest Territories. |
| 37215 | April 1 | Event | 2001 – An EP-3E United States Navy surveillance aircraft collides with a Chinese People's Liberation Army Shenyang J-8 fighter jet. The Navy crew makes an emergency landing in Hainan, China and is detained. |
| 37216 | April 1 | Event | 2001 – Former President of Federal Republic of Yugoslavia Slobodan Milošević surrenders to police special forces, to be tried on war crimes charges. |
| 37217 | April 1 | Event | 2001 – Same-sex marriage becomes legal in the Netherlands, the first contemporary country to allow it. |
| 37218 | April 1 | Event | 2004 – Google announces Gmail to the public. |
| 37219 | April 1 | Event | 2004 – Korea Train Express was opened to traffic from Seoul to –Dongdaegu. |
| 37220 | April 1 | Event | 2006 – The Serious Organised Crime Agency, dubbed the "British FBI", is created in the United Kingdom. |
| 37221 | April 1 | Event | 2009 – Croatia and Albania join NATO. |
| 37222 | April 1 | Event | 2011 – After protests against the burning of the Quran turn violent, a mob attacks a United Nations compound in Mazar-i-Sharif, Afghanistan, resulting in the deaths of thirteen people, including eight foreign workers. |
| 37223 | April 1 | Birth | 1220 – Emperor Go-Saga of Japan (d. 1272) |
| 37224 | April 1 | Birth | 1543 – François de Bonne, Duke of Lesdiguières (d. 1626) |
| 37225 | April 1 | Birth | 1578 – William Harvey, English physician and academic (d. 1657) |
| 37226 | April 1 | Birth | 1610 – Charles de Saint-Évremond, French soldier and critic (d. 1703) |
| 37227 | April 1 | Birth | 1629 – Jean-Henri d'Anglebert, French organist and composer (d. 1691) |
| 37228 | April 1 | Birth | 1640 – Georg Mohr, Danish mathematician and academic (d. 1697) |
| 37229 | April 1 | Birth | 1647 – John Wilmot, 2nd Earl of Rochester, English poet and courtier (d. 1680) |
| 37230 | April 1 | Birth | 1697 – Antoine François Prévost, French author (d. 1763) |