Swift, 25, beat Ariana Grande, Iggy Azalea, Luke Bryan and Sam Smith to become the artist of the year. Her third win came in the best lyrics category for her hit song "Blank Space", said The Hollywood Reoporter.
Sam Smith was announced as the best new artist, while the best collaboration award went to Jessie J, Ariana Grande and Nicki Minaj for "Bang Bang".
"Burnin' It Down" by Jason Aldean got the best country song of the year award and "Don't Tell 'Em" - Jeremih featuring YG bagged the hip hop/R&B song of the year trophy.
Music band 5 Seconds of Summer's fan group 5SOSFAM was given the best fan army award.