Dalton (18-of-29, 168 yards, two interceptions) found Jerome Simpson on a 14-yard scoring strike late in the first quarter, putting the Bengals ahead 10-0.
He gave Cincinnati a 17-3 halftime lead after passing to A.J. Green down the middle for a 43-yard scoring play and the Bengals (5-2) went on to win a fourth straight game for the first time since 2009.
Cincinnati turned the contest into a rout in the fourth quarter when Brandon Tate returned a punt 56 yards for a touchdown and Reggie Nelson added a 75-yard interception return for a score.
Tarvaris Jackson went 21-of-40 through the air for 323 yards and an interception for the Seahawks (2-6).