Edinburgh-headquartered Skyscanner is being bought by Chinese giant Ctrip.com in a deal worth £1.4bn.
The sale marks the latest swoop by a Chinese company for a British firm.
Ctrip.com - which is China's biggest online travel service - said the management of Skyscanner would remain in place and run the company independently.
Launched in 2003 to let users compare prices from different travel sites when searching for flights, hotels and rental cars, Skyscanner is now available in more than 30 languages and has around 60 million monthly active users.
Skyscanner chief executive and co-founder Gareth Williams said the deal took his firm "one step closer to our goal of making travel search as simple as possible for travellers around the world."
The firm employs more than 800 staff, with 10 offices worldwide, including in Barcelona, Beijing, Budapest, Glasgow and London.
Williams said: "This is an important and exciting step in our journey of accelerated global growth.
"Skyscanner will remain operationally independent and continue to deliver the Skyscanner products that travellers know and love."
Ctrip said the takeover would boost its global reach, adding Skyscanner's strength across Europe and a growing presence in the Americas and the Asia-Pacific region.
James Jianzhang Liang, executive chairman at Ctrip, said: "This acquisition will strengthen long-term growth drivers for both companies.
"Skyscanner will complement our positioning at a global scale, and we will leverage our experience, technology and booking capabilities to help Skyscanner."
Calum Paterson, managing partner of SEP and a member of Skyscanner’s board of directors, added: "We are pleased to have played our part in helping Skyscanner become one of the world’s most exciting travel search companies.
"Ctrip is the ideal partner to enable the company to extend its global reach, grow even more rapidly and continue to deliver a fantastic product that is greatly admired by travellers across the world.
"We are particularly pleased that Skyscanner will continue to be headquartered in Edinburgh and to operate independently. We wish the team every success in the future."
Ctrip expects to complete the takeover by the end of the year.
It adds to a string of acquisitions by Chinese companies in search of UK technology, brands and access to foreign markets.
Framestore - the Oscar-winning UK visual effects company behind Gravity and the Harry Potter films - was sold to China's Cultural Investment Holdings earlier this month in a deal valuing the group at £150m.
It also recently emerged that China's second-largest property developer Evergrande Group is in talks to buy British housebuilder Cala, while several Chinese investors are reportedly among consortiums vying to buy a majority stake in National Grid's gas distribution network.