The posters will run in London from January
A campaign to brand bendy buses in London with the slogan "There's probably no God" has raised nearly £140,000 in one week.
The British Humanist Association (BHA) aimed to raise £5,500, but £136,197 has already been donated to the Atheist Bus Campaign.
The BHA will now extend the reach of the campaign to other UK cities and to other forms of transport.
A BHA spokesman said the response to the bus campaign was "overwhelming".
The £136,197 raised has mainly come via small online donations, and includes £23,338 from Gift Aid and £5,500 from prominent atheist Professor Richard Dawkins, a supporter of the Atheist Bus Campaign.
Mr Dawkins agreed to match the BHA's expected amount.
The total of £11,000 would be enough to fund two sets of atheist adverts on 30 London buses for four weeks, which is due to begin in Westminster in January as planned.
The complete slogan reads: "There's probably no God. Now stop worrying and enjoy your life."
The BHA said: "We have been overwhelmed by the public support for the Atheist Bus Campaign.
"It's great that we've exceeded our initial target by so much, but it's been even more amazing that so many of the contributions have come in the form of small donations - this is a real grass roots campaign. "
Due to the unexpected amount raised, the BHA said it hopes to extend the reach of the the campaign to Birmingham, Manchester, and Edinburgh, following the suggestions of supporters.
It also plans to have the slogans on trains and billboards too.
The BHA said that as a result of the campaign the association has 200 new members.