Grosskreutz extends Dortmund contract
The 24-year-old Germany international, who has been at Dortmund since 2009, won two back-to-back league titles in 2011 and 2012 and the German Cup last season.
"We are happy to have secured another crucial element of our team on a long-term basis," sports director Michael Zorc said.
Dortmund have extended deals with several key players including German internationals Mats Hummels and Mario Goetze.
They have yet, however, to renew the contract of top scorer Robert Lewandowski whose deal runs out in 2014 and who has been linked with several top European clubs.