Zorn takes over for Hue Jackson, who left to become offensive coordinator of the Oakland Raiders.
Zorn was fired earlier this month by the Redskins after two seasons as their head coach. Washington was 8-8 in his first year but slumped to 4-12 this season.
He was a quarterbacks coach with the Detroit Lions and Seattle Seahawks before being hired by the Redskins.
Ravens coach John Harbaugh says Zorn "has been a quarterbacks coach, a head coach and he is familiar with our offense. That's a great resume."