The remaining 50% of Australia's largest wind project will continue to be held by Malaysian power producer Malakoff Corporation Berhad.
AGL said the size of the deal equals book value of the project and therefore AGL will not record a profit or loss on the transaction.
The Australian developer will continue to operate and maintain the project and retain the rights to all renewable energy certificates and electricity output until 2038, according to the company.
AGL said the sale was part of its plans to divest A$1 billion in assets by the end of the 2017 financial year. It has 1.9GW of renewable capacity online or in the pipeline.
Macarthur was completed in April 2013, and uses 140 Vestas' V112 3MW turbine.