The partnership will see the Embark name remain on the back of the home and away shorts for the 2017/18 and 2018/19 seasons.
The financial services provider have enjoyed a lengthy relationship with the club, with Rotherham United’s commercial director Steve Coakley heralding the announcement of another successful commercial deal for the Millers.
“Our partnership with Embark has proven to be one of our most successful, so we are obviously thrilled to extend our association for the next two seasons.
“Having the Embark logo on the back of our home and away shorts is great exposure for their brand, but the partnership goes much deeper than the name.
“They are passionate about the club, they attend all the home games and are involved in several other areas of the commercial operation.
“I have personally enjoyed a great relationship with Phil Smith and his colleagues, and I look forward to a long and prosperous future for both parties.”
Embark director Phil Smith added:
"We are absolutely delighted to further extend our now long standing sponsorship of the Millers.
"This club represents tenacity, professionalism and community. These are values we are investing in and it is terrific to associate our national business with the club."