Co-hosted by The Voice coach Blake Shelton and country artist Luke Bryan, the Academy of Country Music Awards took place at the MGM Grand Garden Arena in Las Vegas. Although Shelton did not win any awards this year, he was nominated multiple times for different honors.
Musgraves, who finished seventh on the fifth season of Nashville Star back in 2007, won Album of the Year for "Same Trailer Different Park."
"Thank you so much. I can tell you I really did not expect this one. Luke Laird and Shane McAnally, I got to produce this record with [them], and I'm so proud of it -- all the wonderful musicians that played on the record, the songwriters that made these songs a reality. I just want to say that I'm really proud to be a woman representing country music," Musgraves said in her acceptance speech.
Musgraves beat out Shelton's "Based on a True Story" for the win.
Female Vocalist of the Year went to Lambert, who finished in third place on Nashville Stars' original 2003 season and also served as an advisor to "Team Shakira" on The Voice's currently-airing sixth season.
"I cannot believe this. I really didn't expect it ya'll, thank you so much. I was just hanging out with Trisha Yearwood back there. Holy crap! And I was standing next to [nominee] Sheryl Crow, a complete and utter rockstar. And Kacey Musgraves, I grew up with her. She wrote the Single of the Year this year," Lambert said when accepting her award.
"And Carrie Underwood's my buddy ya'll, and she's phenomenal. I can't believe it. I'm so grateful and thankful and humbled. I love my job! Thank you fans and thank you country music. I want to send this one to a friend who's going through a hard time right now at home in Texas... and the little angel in heaven. This one's for ya'll tonight."
Lambert bested Musgraves and Underwood, American Idol's fourth-season winner, for the honor.
Lambert also won the award for Single Record of the Year for "Mama's Broken Heart."