His total worth was estimated at $76bn (£45.5bn) this year, up from $67bn in 2013.
Bill and Melinda Gates have given billions away and still have a few pennies left over
The Microsoft founder has knocked last year's leader Carlos Slim of Mexico off the top spot. In all the software mogul has headed the list for 15 of the last 20 years.
Bill has donated $28 billion to poverty eradication and health projects through his charitable foundation in hopes of improving the lives of those less fortunate.
"Money has no utility to me beyond a certain point," he told the Telegraph in a recent interview. "Its utility is entirely in getting the resources out to the poorest in the world."
Mark Zuckerberg is worth $28.5bn
In third spot is Zara boss Spain's Amancio Ortega with $64bn. His daughter Marta surprised fellow Spaniards with her low-key nuptials in 2012, to which she wore a Zara dress. Her groom showjumper Sergio Alvarez, meanwhile, wore a suit by Massimo Dutti, an affordable label also owned by his father-in-law.
Technology features heavily in the list, with Facebook founder Mark Zuckerberg, the social network's chief operating officer Sheryl Sandberg, and WhatsApp founders Jan Koum and Brian Acton all making the cut.
Mark also hit the headlines in 2012 when he married his university sweetheart, doctor Priscilla Chan in a modest ceremony in the back yard of their California home, with catering by their local restaurant.
The Duke of Westminster with wife Natalia and one of their four children, Viola
Britain's wealthiest man is the Gerald Grosvenor, the Duke of Westminster, who is number 81 on the list overall. His 23-year-old heir Hugh, whose formal title is Earl Grosvenor, gained prominence last year when he was named as one of Prince George's godfathers.
Hugh's mother Natalia was a close friend of Princess Diana and is one of Prince William's godmothers. The late Princess was asked by Natalia to be godmother to her daughter Lady Edwina Grosvenor.