Boeing this morning confirmed that the Istanbul-hubbed airline had placed the order, which was initially announced on the carrier's investor relations website on December 29.
The airline said the aircraft would be delivered this year.
"These freighter orders will surely contribute to our significant target for establishing a young and efficient cargo fleet," said M. İlker Aycı, chairman of the board and the executive committee of Turkish Airlines.
"The new aircraft will be delivered this year and will provide us with additional flexibility to serve more destinations while we continue to develop our global freight service."
According to its third quarter report, prior to the delivery of the first two B777Fs, The Turkish Airlines freighter fleet stood at nine A330-200Fs on financial lease and six wet leased aircraft, although it does not reveal what these aircraft are.
Boeing said the new B777Fs would help Turkish increase operational flexibility.
"The B777 Freighter is the largest and most capable twin-engine freighter in the world today," said Marty Bentrott, senior vice president of sales, Middle East, Turkey, Russia, Central Asia and Africa, Boeing Commercial Airplanes. "We're pleased world-class customers like Turkish Airlines recognize the value of the 777 Freighter's long range and large payload capability."
The B777F is the world's longest-range twin-engine freighter and can fly just over 9,000km with a full payload of 112 tons.
"The airplane's range capability translates into significant savings for airlines: fewer stops and associated landing fees, less congestion at transfer hubs, lower cargo handling costs and shorter cargo delivery time," Boeing added.