The club's playing kit and trainwear has been produced by adidas since 2009 and that is set to continue in the Premier League next season and beyond.
Boro Chief Executive Officer Neil Bausor said: "We're delighted to extend our partnership with adidas and are looking forward to working together in the Premier League."
Gavin Thomson, adidas Managing Director, North Europe, said: "We are proud of the progress made by the club as they return to the top flight.
"We are excited by the prospect of continuing to grow the partnership as the club move into that next chapter."
The club are poised to unveil the latest development with adidas with the new home and away kits for the 2016/17 Premier League return.