The budget carrier said in February it had ordered three A330-200s with a total list price of $492 million that are scheduled for delivery from 2014, bringing the number of A330s on order to 28.
The GE deal, which was signed in New York on Wednesday, will see the company provide maintenance, repair and overhaul of the engines as part of a 20-year agreement, the airline said in a statement.
"AirAsia X's acquisition of the new technologically more advanced and fuel-efficient GE engines would help us accentuate our network expansion while holding true to our business model," airline chairman Rafidah Aziz said.
GE Aviation's general manager of global sales Kevin McAllister said the engine "will help AirAsia X maintain one of the youngest and fuel efficient fleets in the sky."
AirAsia X carried 1.92 million passengers last year. Its 14 destinations include London, Tehran, Tokyo, Delhi and Melbourne.