The Jaguars scored the game's final 12 points, six of them on field goals of 54 and 28 yards by Josh Scobee -- who also had a 26-yarder in the second period.
David Garrard completed 7-of-12 for 99 yards with an interception while leading the Jacksonville offense for the first three series.
Atlanta starter Matt Ryan was 7-of-15 for 116 yards and a touchdown during the first half. Ryan's touchdown throw went for 76 yards to Harry Douglas.
Jacksonville is 1-1 in exhibition play and Atlanta has lost its two games.