The Tass River is a river of the West Coast Region of New Zealand's South Island. It flows predominantly northeast from its origins in the Southern Alps east of Lake Hochstetter, reaching the Upper Grey River close to the southern tip of the Victoria Forest Park.

• List of rivers of New Zealand

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

42°27′S 171°59′E / 42.450°S 171.983°E / -42.450; 171.983