David Wilson rushed for 132 yards and a 10.
"I thought we played hard throughout," Virginia Tech head coach Frank Beamer said. "I thought they played hard, throughout the game. I thought we do some very good things, and then we don���t do some things very consistently. That���s where we are as a football team right now."
Logan Thomas completed 22-of-33 passes for 229 yards and added a rushing score for the Hokies (4-0), who have won their first four games for the first time since 2006.
Virginia Tech opens up its ACC slate next Saturday by hosting 4-0 Clemson at Lane Stadium.
Danny Coale and D.J. Coles combined for 173 receiving yards on 15 catches. Coles had 66 yards on eight catches, while Coale pulled down seven balls for 107 yards.
Rakeem Cato threw for 245 yards and a score on 17-of-33 passing for Marshall (1-3), while Aaron Dobson caught five passes for 103 yards and a touchdown.
Marshall was held to six yards rushing on 24 total carries in defeat.
The Hokies struck first with a touchdown on their second possession. Wilson took a sweep to the left side for 28 yards to the Marshall three, and two snaps later, Thomas rumbled in from five yards out.
After a Marshall three-and-out, the Hokies marched 58 yards on six plays for another touchdown. The drive was highlighted by a 22-yard pass completion to Coles on a nice throw from Thomas, and Wilson punched it in from the three to increase the advantage to 13-0. The extra point was blocked and nearly returned the other way by the Thundering Herd.
Tyler Warner booted a 45-yard field goal for Marshall to put them on the board early on in the second quarter.
A key pass interference penalty on a 3rd-and-6 kept the Hokie drive alive on their next possession. They capitalized and scored a third straight touchdown when Josh Oglesby fought for a tough four-yard score to make it 20-3.
Cody Journell kicked a 41-yard field goal to increase Virginia Tech's lead to 20 as Coale had a key 20-yard catch on the drive.
Three consecutive completions by Cato led to a touchdown with just 32 seconds left in the half for Marshall. Cato had a 12-yard pass to Gator Hoskins, a 30- yard dart to Antavious Wilson, and a 29-yard touchdown pass down the left sideline to Dobson. Virginia Tech took a 23-10 lead into the locker room.
"I saw man-to-man coverage. I just wanted to get a completion. I saw it and took a shot," Cato said on his touchdown pass to Dobson.
Virginia Tech's first drive of the second half stalled, but Antone Exum intercepted a Cato pass on the Thundering Herd's ensuing possession. He returned it 36 yards to Marshall's 29-yard line, but Journell missed a 37-yard field goal.
James Gayle sliced through the middle of the Marshall offensive line on a critical 3rd-and-1 in Virginia Tech territory late in the third quarter and wrapped up Travon Van for a two-yard loss as the Thundering Herd were forced to punt.
Oglesby took an inside handoff 44 yards to the Marshall 11-yard line, and finished off the 86-yard, eight-play drive with a five-yard plunge to give the Hokies a 30-10 advantage early on in the fourth quarter.
Marshall's Monterius Lovett intercepted Thomas, and recovered a Wilson fumble on consecutive Virginia Tech possessions, but the Thundering Herd couldn't turn the mistakes into points.
The Hokies have picked off at least one pass in each of their last 11 games. Exum became the sixth different Virginia Tech player to record an interception this season...Virginia Tech leads the all-time series 9-2, and has won seven straight in the series. Marshall hasn't defeated the Hokies since 1940.