The Mason River is a river of the north Canterbury region of New Zealand's South Island. It flows south from the Amuri Range, at the foot of the Mason Hills before turning southwest to reach the Waiau River just to the west of the township of Waiau.

• List of rivers of New Zealand

"Place name detail: Mason River". New Zealand Gazetteer. New Zealand Geographic Board. Retrieved 12 July 2009.

42°39′S 173°02′E / 42.650°S 173.033°E / -42.650; 173.033