- Jan 15 Wikipedia a free Wiki content encyclopedia is launched by Jimmy Wales and Larry Sanger
- Feb 12 NEAR Shoemaker spacecraft touchdown in the "saddle" region of 433 Eros becoming the first spacecraft to land on an asteroid.
- Feb 15 First draft of the complete human genome is published in the journal "Nature"
- Apr 1 Netherlands becomes the first country in the world to make same-sex marriage legal
- Sep 11 Two passenger planes hijacked by terrorists crash into New York's World Trade Towers causing the collapse of both and deaths of 2,752 people
- Sep 11 Terrorists hijack a passenger plane and crash it into the Pentagon causing the deaths of 125 people
- Sep 11 Attempt by passengers and crew of United Airlines Flight 93 to retake control of their hijacked plane from terrorists causes plane to crash in Pennsylvania field killing all 64 people on board
- Sep 20 In an address to a joint session of Congress and the American people, U.S. President George W. Bush declares a "war on terror".
- Oct 7 The U.S. invasion of Afghanistan starts with an air assault and covert operations on the ground
- Oct 8 U.S. President George W. Bush announces the establishment of the Office of Homeland Security.
During a trip to Syria, Pope John Paul II becomes the first pope to enter a mosque.
On May 6, 2001
- Jun 10 Sasha [Natasha] Obama, American daughter of Barack and Michelle Obama, born in Chicago, Illinois
- Jun 24 Mo'ne Davis, American Little League baseball pitcher, 1st girl to pitch a shutout, born in Philadelphia, Pennsylvania
- Oct 7 Princess Senate Seeiso, daughter of King Letsie III of Lesotho
- Oct 14 Rowan Blanchard, American actress (Girl Meets World) and activist, born in Los Angeles, California
- Oct 18 Annelise Manojlovic, English actress