The group, which owns booking.com, KAYAK, priceline.com, agoda.com, rentalcars.com and OpenTable, announced the deal on Tuesday (July 10).
Sydney-based HotelsCombined will report to the group’s KAYAK brand, boosting its reach in the Asia Pacific region for the first time.
Glenn Fogel, Booking Holdings chief executive, said: "HotelsCombined has built a strong brand with loyal consumers across APAC. We believe the team will be a great addition to KAYAK to further expand our worldwide metasearch strategy.”
KAYAK chief executive Steve Hafner added: "We’ve admired their execution for many years. I’m eager to work together to strengthen our capabilities and global network.”
Hotel metasearch engine HotelsCombined was founded in 2005 and supports a number of affiliates while powering various travel search platforms.
Its board and stockholders have approved the acquisition, which is expected to be completed later this year subject to regulatory approval and conditions.
Hichame Assi, HotelsCombined chief executive, said: "We’ve always been inspired by the entrepreneurial culture of Booking Holdings brands and are excited to be joining the family.
“Operating under the KAYAK umbrella will strengthen our proposition to both customers and partners with greater scale, product breadth and innovation."