The Atheist Bus Campaign aims to place "peaceful and upbeat" messages about atheism on transport media in Britain, in response to evangelical Christian advertising.

It was created by comedy writer Ariane Sherine and launched on 21 October 2008, with official support from the British Humanist Association and Richard Dawkins. The campaign's original goal was to raise £5,500 to run 30 buses across London for four weeks early in 2009 with the slogan: "There’s probably no God. Now stop worrying and enjoy your life".

Richard Dawkins, author of The God Delusion, agreed to match all donations up to a maximum of £5,500, providing a total of £11,000 if the full amount were to be raised. The campaign reached that target by 10:06AM on 21 October and had raised £100,000 by the evening of 24 October. The campaign closed on 11 April 2009, having raised a total of £153,516.51.

The first buses started running on 6 January 2009 – 800 are running around the whole of the UK and it is also planned to place 1,000 adverts on the London Underground featuring quotations from famous atheists. Subsequently, two large LCD screens have been placed on Oxford Street, central London.

Clinton Richard Dawkins, FRS, FRSL (born 26 March 1941), known as Richard Dawkins, is a British ethologist, evolutionary biologist and author. He is an emeritus fellow of New College, Oxford, and was the University of Oxford's Professor for Public Understanding of Science from 1995 until 2008.

Dawkins came to prominence with his 1976 book The Selfish Gene, which popularised the gene-centered view of evolution and introduced the term meme. In 1982 he introduced an influential concept into evolutionary biology, presented in his book The Extended Phenotype, that the phenotypic effects of a gene are not necessarily limited to an organism's body, but can stretch far into the environment, including the bodies of other organisms.

Dawkins is an atheist, a vice president of the British Humanist Association, and a supporter of the Brights movement. He is well known for his criticism of creationism and intelligent design. In his 1986 book The Blind Watchmaker, he argued against the watchmaker analogy, an argument for the existence of a supernatural creator based upon the complexity of living organisms. Instead, he described evolutionary processes as analogous to a blind watchmaker. He has since written several popular science books, and makes regular television and radio appearances, predominantly discussing these topics. In his 2006 book The God Delusion, Dawkins contends that a supernatural creator almost certainly does not exist and that religious faith is a delusion—"a fixed false belief." As of January 2010 the English-language version has sold more than two million copies and had been translated into 31 languages.