The 30-year-old has spent the last four seasons with Schalke, but is now looking forward to a fresh challenge at the Mercedes-Benz Arena after jumping at the chance to complete a move.
"I didn't have to spend much time considering the offer from VfB and I am very happy that the transfer has worked out," he told the club's official website.
"I am very motivated and extremely eager to get on the ball and begin training with the team. During the course of my career I have played in Stuttgart on a number of occasions, so I know there is always an unbelievable atmosphere here. That too was an important factor in me making this move to VfB."
Marketing director Jochen Rottgermann is also delighted with the swoop of the left-sided star: "In Dennis Aogo, we have secured the services of a nationally and internationally very experienced player, who has proven his qualities wherever he has played.
"He knows the Bundesliga very well and will thus need little time to get integrated. We are very happy to have been able to convince him of the direction we are taking."