Underwood, who won on "American Idol" in 2005, earned Best Female Country Vocal Performance honors for "Jesus, Take the Wheel," which also was named Best Country Song.
Underwood also was named Best New Artist.
Gill earned honors in the Best Male Country Vocal Performance category for "The Reason Why."
Bon Jovi and Jennifer Nettles' "Who Says You Can't Go Home" was selected Best Country Collaboration with Vocals.
Bryan Sutton and Doc Watson claimed Best Country Instrumental Performance for "Whiskey Before Breakfast."