Qatar will buy 24 Typhoon fighter jets worth $8bn from the United Kingdom as the Gulf state continues to stock up on high-tech weaponry.
The deal between the two countries was signed in Doha by Qatar's Defence Minister Khalid bin Mohammed al-Attiyah and his British counterpart, Gavin Williamson.
It is the biggest order for Typhoon fighters in more than a decade.
"These formidable jets will boost the Qatari military's mission to tackle the challenges we both share in the Middle East, supporting stability in the region and delivering security at home," Williamson said.
The deal for the Typhoon jets also includes training of air force personnel, the statement said.
The two countries also agreed to create a Joint Operation Squadron, the start of a partnership between Qatar's air force and Britain's Royal Air Force (RAF).
"The squadron tackles all air combat operations, ensuring combat readiness for all Qatari and British pilots and technicians," said the statement.