The club has announced that the 28-year-old has signed a three-year deal.
Whitelock has played sevens Tests for the All Blacks.
Highlanders teammate and All Black outside back Ben Smith announced in December that he has heading to Pau at the end of the year.
Pau are coached by Simon Mannix and the club has a number of New Zealanders playing including Jamie McIntosh, Peter Saili, Colin Slade and Tom Taylor.
They are currently 11th in the Top 14 championship.