Rosler, 45, joins from League One (third tier) Brentford after compensation was agreed and replaces Owen Coyle, who left Wigan less than six months after taking over from Spaniard Roberto Martinez.
"Uwe is one of the brightest young managers in the Football League and his ambition is to manage in the Premier League," Wigan chairman Dave Whelan told the club website (www.wiganlatics.co.uk).
"He impressed me enormously when I spoke to him, he has a strong philosophy about how to play the game and has a desire to shape all aspects of the long term future of the club. I think he can and will achieve great things here at Wigan Athletic."
Wigan, relegated from the top flight last season after stunning Manchester City 1-0 to win the FA Cup, are currently 14th in the Championship.
They are third in Europa League Group D but can still qualify for the knockout stages.