Bender's current deal was not due to expire until the summer of 2013 but his form this season has attracted interest from elsewhere, prompting Dortmund to act.
The 21-year-old joined Jurgen Klopp's side from 1860 Munich in the summer of 2009 and has become an integral part of a Dortmund side which has established an 11-point lead at the top of the table following a blistering start.
He said: "I did the right thing when I joined Dortmund.
"And I want to be around when Dortmund continues to build in the future."
Dortmund sporting director Michael Zorc said: "Sven is an important player in our future planning."