Lonely Planet founders Maureen and Tony Wheeler will keep a 25 percent stake, the BBC said on Monday.
The couple, who met on a bench in London's Regents Park, started the publisher in 1972 after a honeymoon trip across Asia with "a beat-up old car, a few dollars in the pocket and a sense of adventure," the Lonely Planet's Web site says.
More than thirty years after "Across Asia on the Cheap," the couple have made about 70 million pounds on the sale, figures from the source suggest, since they owned about 90 percent of the business.
"Joining BBC Worldwide allows us to secure the long-term future of our company within a globally recognised media group," the Wheelers said in a statement.
Lonely Planet, headquartered in Melbourne, Australia, publishes about 500 travel guides, including language, cycling and walking titles. The company, which employs 500 staff and as many as 300 on-the-road authors, has recently targeted a mature travelling audience after focusing on campers and backpackers for decades.
The deal will help the BBC become "one of the world's leading content businesses," BBC Worldwide Chief Executive John Smith said.
The broadcaster also aims to grow online brands and to increase its operations in Australia and North America, Smith said.
"The association will strengthen Lonely Planet's visibility and growth potential, particularly in the digital arena, as well as providing their users access to the wide range of BBC content which connects with their interests," said Etienne de Villiers, non-executive chairman of BBC Worldwide.
Deloitte Corporate Finance and Blake, Dawson Waldron advised the BBC on the purchase, the broadcaster said.