Zach Hocker's 42-yard field goal with under seeded 28.
Vanderbilt kicker Carey Spear had a chance to tie the game with 12 seconds showing on the clock, but he missed a 27-yard chip shot.
Tyler Wilson completed 27-of-43 passes for 316 yards and a touchdown for the Razorbacks (7-1, 3-1 SEC), who are off to their best start under head coach Bobby Petrino.
Dennis Johnson carried the ball nine times for 52 yards for Arkansas, which has won five straight games against opponents from the SEC's Eastern Division, the longest winning streak against Eastern Division foes in school history.
Jarius Wright caught 10 passes for 135 yards and a score for the Razorbacks, who have won four in a row.
Jordan Rodgers completed 15-of-27 passes for 240 yards and a touchdown for the Commodores (4-4, 1-4), who have lost four of five since starting the season with three straight wins. Rodgers also carried the ball 18 times for 66 yards and two scores.
Zac Stacy rushed for 128 yards and a touchdown on 19 carries to go along with three catches for 51 yards. Jordan Matthews hauled in six passes for 151 yards and a touchdown.