Next season four teams will fight with Mercedes power, McLaren, Force India, Williams and Engine squad.
"The proud heritage of Williams and the company's commitment to technological excellence make it a perfect long-term partner for Mercedes-Benz under the new powertrain regulations," Wolff told Autosport.
"It is a win-win situation for both HPP [Mercedes-Benz High Performance Powertrains] and Williams, which will ensure HPP is able to supply at least three teams on a long term basis under the new regulations and could open interesting new perspectives for technology transfer.
"We look forward to enjoying much success together over the coming years."
