| 91111 | August 12 | Event | 1969 – Violence erupts after the Apprentice Boys of Derry march in Derry, Northern Ireland, United Kingdom resulting in a three-day communal riot known as the Battle of the Bogside. |
| 91112 | August 12 | Event | 1976 – Between 1,000 and 3,500 Palestinians are killed in the Tel al-Zaatar massacre, one of the bloodiest events of the Lebanese Civil War |
| 91113 | August 12 | Event | 1977 – The first free flight of the Space Shuttle Enterprise. |
| 91114 | August 12 | Event | 1977 – The 1977 riots in Sri Lanka, targeting the minority Sri Lankan Tamil people, begin, less than a month after the United National Party came to power. Over 300 Tamils are killed. |
| 91115 | August 12 | Event | 1978 – The Treaty of Peace and Friendship between Japan and the People's Republic of China is signed. |
| 91116 | August 12 | Event | 1980 – The Montevideo Treaty, establishing the Latin American Integration Association, is signed. |
| 91117 | August 12 | Event | 1981 – The IBM Personal Computer is released. |
| 91118 | August 12 | Event | 1982 – Mexico announces that it is unable to pay its enormous external debt, marking the beginning of a debt crisis that spreads to all of Latin America and the Third World. |
| 91119 | August 12 | Event | 1985 – Japan Airlines Flight 123 crashes into Osutaka ridge in Gunma Prefecture, Japan, killing 520, to become the worst single-plane air disaster. |
| 91120 | August 12 | Event | 1990 – Sue, the largest and most complete Tyrannosaurus Rex skeleton found to date, is discovered by Sue Hendrickson in South Dakota. |
| 91121 | August 12 | Event | 1992 – Canada, Mexico and the United States announce completion of negotiations for the North American Free Trade Agreement (NAFTA). |
| 91122 | August 12 | Event | 1994 – Major League Baseball players go on strike. This will force the cancellation of the 1994 World Series. |
| 91123 | August 12 | Event | 2000 – The Oscar class submarine K-141 Kursk of the Russian Navy explodes and sinks in the Barents Sea during a military exercise. |
| 91124 | August 12 | Event | 2005 – Sri Lanka's foreign minister, Lakshman Kadirgamar, is fatally shot by an LTTE sniper at his home. |
| 91125 | August 12 | Event | 2007 – The bulk carrier MV New Flame collides with the oil tanker Torm Gertrud at the southernmost tip of Gibraltar, ending up partially submerged. |
| 91126 | August 12 | Event | 2012 – The closing ceremony of the Summer Olympics are held at the Olympic Stadium in London. |
| 91127 | August 12 | Event | 2015 – At least two massive explosions kill 145 people and injure nearly 800 in Tianjin, China. |
| 91128 | August 12 | Birth | 1503 – Christian III of Denmark (d. 1559) |
| 91129 | August 12 | Birth | 1566 – Isabella Clara Eugenia Spanish wife of Albert VII, Archduke of Austria (d. 1633) |
| 91130 | August 12 | Birth | 1604 – Tokugawa Iemitsu, Japanese shogun (d. 1651) |
| 91131 | August 12 | Birth | 1644 – Heinrich Ignaz Franz Biber, Bohemian-Austrian violinist and composer (d. 1704) |
| 91132 | August 12 | Birth | 1647 – Johann Heinrich Acker, German pastor and educator (d. 1719) |
| 91133 | August 12 | Birth | 1686 – John Balguy, English philosopher and author (d. 1748) |
| 91134 | August 12 | Birth | 1696 – Maurice Greene, English organist and composer (d. 1755) |
| 91135 | August 12 | Birth | 1720 – Konrad Ekhof, German actor (d. 1778) |
| 91136 | August 12 | Birth | 1762 – George IV of the United Kingdom (d. 1830) |
| 91137 | August 12 | Birth | 1774 – Robert Southey, English poet and author (d. 1843) |
| 91138 | August 12 | Birth | 1773 – Karl Faber, Prussian historian and academic (d. 1853) |
| 91139 | August 12 | Birth | 1831 – Helena Blavatsky, Russian theosophist and scholar (d. 1891) |
| 91140 | August 12 | Birth | 1852 – Michael J. McGivney, American priest, founded the Knights of Columbus (d. 1890) |