The 7 July 2005 London bombings, often referred to as 7/7, were a series of four coordinated suicide attacks carried out by Islamist terrorists in London that targeted commuters travelling on the city's public transport system during the morning rush hour.

Three terrorists separately detonated three homemade bombs in quick succession aboard London Underground trains across the city and, later, a fourth terrorist detonated another bomb on a double-decker bus in Tavistock Square. The train bombings occurred on the Circle line near Aldgate and at Edgware Road, and on the Piccadilly line near Russell Square.

Apart from the bombers, 52 UK residents of 18 different nationalities were killed and more than 700 were injured in the attacks, making it the UK's deadliest terrorist incident since the 1988 bombing of Pan Am Flight 103 near Lockerbie, as well as the country's first Islamist suicide attack.

The explosions were caused by improvised explosive devices made from triacetone triperoxide, packed into backpacks. The bombings were followed two weeks later by a series of attempted attacks that failed to cause injury or damage.