German media reported that Leverkusen paid in the region of 15 million euros ($17.1m) for the 28-year-old...
German media reported that Leverkusen paid in the region of 15 million euros ($17.1m) for the 28-year-old, who started just three Bundesliga games last season and hasn't played a full international since 2013.
The brothers were named joint players of the tournament at the under-19 European Championship in 2008 and Lars has also played for the senior national side.
The pair played together at club level at 1860 Munich, but not since 2009, when Lars moved to Leverkusen and Sven signed for Dortmund.
"Just like his brother Lars, Sven has qualities the team need," said Leverkusen coach Heiko Herrlich.
"His mentality and team spirit make him a leader on and off the pitch. Having both brothers on the team is just great."
Sven Bender spent eight seasons at Dortmund, winning the Bundesliga twice in 2011 and 2012.