The Frogs led just 3-0 with two minutes left before halftime when a sack forced the Cougars to punt from their 4-yard line. Given good field position, Dalton found Josh Boyce on a 35-yard score two plays later.
TCU (7-0, 3-0 Mountain West) got the ball right back on an interception, and Dalton hit a wide-open Jimmy Young in the end zone for a 14-yard score that made it 17-0 with 26 seconds left in the half.
BYU (2-5, 1-2) had just 14 total yards in the first half but ended TCU's shutout streak at 10 quarters with a 70-yard drive to a short field goal late in the third.
The Cougars didn't pick up a first down until early in the second quarter and didn't cross midfield the until shutout-ending field goal drive. BYU finished with 147 total yards, the third straight time and fourth overall that TCU's nation-leading defense held an opponent to less than 200 yards.
The Frogs weren't much better offensively most of the first half. They finally broke through late in the first quarter thanks to a short field, with Dalton's 20-yard run -- his 20th first-down run of the season -- setting up a short field goal.
BYU's longest current losing streak against a Mountain West opponent is now at three, by a combined score of 101-17. BYU might not get another crack at TCU for some time, since the Cougars are going independent after this season.
The Cougars kept TCU close early with several hard hits in the first half, including a blind-side sack of Dalton by Corby Eason that knocked the Frogs out of field goal range.
Dalton still had another strong passing game -- his fourth in four home games. He went 24 of 36 for 273 yards with four touchdowns and no interceptions. He has now thrown for 992 yards, with 10 touchdowns and no interceptions at home.
Ed Wesley, TCU's leading rusher, had a rough first quarter, starting when he scrambled 20 yards behind the line of scrimmage to recover a bad shotgun snap and came up limping after he was swarmed by BYU defenders. He left the game again later in the quarter with his left arm hanging to his side. But he came back again, finishing with 53 yards on 10 carries.
The Frogs padded the lead in the fourth quarter, just as they did two weeks ago when they led Colorado State just 6-0 at halftime before winning 27-0. This time, it was a pair of Dalton touchdown passes, starting with the second Dalton-to-Boyce connection -- a 20-yard pass where Boyce avoided a defender at the 10 and stretched the ball across the goal line as he was being tackled.
Dalton's final scoring pass was a 21-yarder to Jeremy Kerley on fourth-and-3 that put the Frogs ahead 31-3 with 4:26 remaining.
Tanner Brock led TCU with 11 tackles, including a stuff of BYU running back Bryan Kariya for a 1-yard loss on fourth-and-1 from the BYU 47 on the first series of the second half.
With BYU's running game struggling, freshman quarterback Jake Heaps had a difficult day. He completed just 14 of 30 passes for 91 yards with two interceptions.