The Swedish international moves to the Premier League club on a four-year deal for an undisclosed fee.
Following a successful trial, Olsson joined Rovers as a 17-year-old from Swedish side Högaborgs BK in January 2006. The full-back quickly progressed through the Academy and Reserves to become a valuable member of the first team squad.
During his time with Rovers he would go on to make 143 appearances, scoring six goals and became a regular for his national side.
Blackburn Rovers would like to wish Martin every success in the future.