| 94351 | August 20 | Event | 1986 – In Edmond, Oklahoma, U.S. Postal employee Patrick Sherrill guns down 14 of his co-workers and then commits suicide. |
| 94352 | August 20 | Event | 1988 – "Black Saturday" of the Yellowstone fire in Yellowstone National Park |
| 94353 | August 20 | Event | 1988 – Peru becomes a member of the Berne Convention copyright treaty. |
| 94354 | August 20 | Event | 1988 – Iran–Iraq War: A ceasefire is agreed after almost eight years of war. |
| 94355 | August 20 | Event | 1988 – The Troubles: Eight British soldiers are killed and 28 wounded when their bus is hit by an IRA roadside bomb in Ballygawley, County Tyrone. |
| 94356 | August 20 | Event | 1989 – The pleasure boat Marchioness sinks on the River Thames following a collision. Fifty-one people are killed. |
| 94357 | August 20 | Event | 1989 – The O-Bahn Busway in Adelaide, the world's longest guided busway, opens. |
| 94358 | August 20 | Event | 1991 – Dissolution of the Soviet Union, August Coup: More than 100,000 people rally outside the Soviet Union's parliament building protesting the coup aiming to depose President Mikhail Gorbachev. |
| 94359 | August 20 | Event | 1991 – Estonia, annexed by the Soviet Union in 1940, issues a decision on the re-establishment of independence on the basis of historical continuity of its pre-World War II statehood. |
| 94360 | August 20 | Event | 1993 – After rounds of secret negotiations in Norway, the Oslo Accords are signed, followed by a public ceremony in Washington, D.C. the following month. |
| 94361 | August 20 | Event | 1997 – Souhane massacre in Algeria over 60 people are killed and 15 kidnapped. |
| 94362 | August 20 | Event | 1998 – The Supreme Court of Canada rules that Quebec cannot legally secede from Canada without the federal government's approval. |
| 94363 | August 20 | Event | 1998 – U.S. embassy bombings: The United States launches cruise missile attacks against alleged al-Qaeda camps in Afghanistan and a suspected chemical plant in Sudan in retaliation for the August 7 bombings of American embassies in Kenya and Tanzania. |
| 94364 | August 20 | Event | 2002 – A group of Iraqis opposed to the regime of Saddam Hussein take over the Iraqi Embassy in Berlin, Germany for five hours before releasing their hostages and surrendering. |
| 94365 | August 20 | Event | 2008 – Spanair Flight 5022, from Madrid, Spain to Gran Canaria, skids off the runway and crashes at Barajas Airport. Of the 172 people on board, 146 die immediately, and eight more later die of injuries sustained in the crash. |
| 94366 | August 20 | Event | 2012 – A prison riot in the Venezuelan capital, Caracas, kills at least 20 people. |
| 94367 | August 20 | Event | 2014 – Seventy-two people are killed in Japan's Hiroshima Prefecture by a series of landslides caused by a month's worth of rain that fell in one day. |
| 94368 | August 20 | Birth | 1517 – Antoine Perrenot de Granvelle, French cardinal and art collector (d. 1586) |
| 94369 | August 20 | Birth | 1561 – Jacopo Peri, Italian singer and composer (d. 1633) |
| 94370 | August 20 | Birth | 1613 – Duchess Elisabeth Sophie of Mecklenburg (d. 1676) |
| 94371 | August 20 | Birth | 1625 – Thomas Corneille, French playwright and philologist (d. 1709) |
| 94372 | August 20 | Birth | 1632 – Louis Bourdaloue, French preacher and academic (d. 1704) |
| 94373 | August 20 | Birth | 1710 – Thomas Simpson, English mathematician and academic (d. 1761) |
| 94374 | August 20 | Birth | 1719 – Christian Mayer, Czech astronomer and educator (d. 1783) |
| 94375 | August 20 | Birth | 1720 – Bernard de Bury, French harpsichord player and composer (d. 1785) |
| 94376 | August 20 | Birth | 1752 – Landgravine Friederike of Hesse-Darmstadt (d. 1782) |
| 94377 | August 20 | Birth | 1778 – Bernardo O'Higgins, Chilean general and politician, 2nd Supreme Director of Chile (d. 1842) |
| 94378 | August 20 | Birth | 1779 – Jöns Jacob Berzelius, Swedish chemist and academic (d. 1848) |
| 94379 | August 20 | Birth | 1799 – James Prinsep, English orientalist and scholar (d. 1840) |
| 94380 | August 20 | Birth | 1833 – Benjamin Harrison, American general, lawyer, and politician, 23rd President of the United States (d. 1901) |