Tyson Johnson grabbed a game-high 10 rebounds for the Cowboys (11-2), who were playing in the four-team Duel in the Desert holiday tournament hosted by Utah State.
Wyoming went on a 13-2 run early in the first half and took a 48-33 lead into the break. The Cowboys led by double digits for most of the second half.
Howard (1-10) came to within 50-45 with 13:50 to play on a short jumper by Paul Kirkpatrick. But two 3-pointers by Ewing and four second-half steals helped the Cowboys extend their lead to as much as 80-63 with 3:44 to play.
Chris McHenry led Howard with 29 points, while Eugene Wyatt added 20 and Kirkpatrick finished with 12.