The 24-year-old Gabonese striker joins the Bundesliga and Champions league runners-up Borussia Dortmund from French side AS Saint-Etienne.
''We're pleased to have got our man in Pierre-Emerick Aubameyang, He's extremely versatile in the forward positions, has exceptional speed and is a real goal threat'' said Dortmund's sporting director Micahel Zorc.
The 24-year-old striker scored 19 goals and set-up 14 goals last season, he ended as the Ligue 1 second-highest scorer.
The Gabonese striker will join his new team-mates when they return from their Austrian training camp in Tirol.