Boller was playing in place of Steve McNair, who injured his passing hand in the second quarter. He went 13-for-21 for 238 yards as the Ravens won for the seventh time in their last eight games.
They had only a 17-10 halftime advantage.
Jamal Lewis scored once on 22 carries for 109 yards, while both Demetrius Williams and Ovie Mughelli caught touchdown passes for the Ravens, who earned a bye for the first weekend of the AFC playoffs.
Derek Anderson was 23-for-32 for 223 yards, two touchdowns and two interceptions for the Browns (4-10), who have lost four of their last five games.