"There's a strong argument that [Adele] could be No. 1 and we welcome that back-and-forth," said Eric Ditzian, MTV's senior news director. "We wanted to take into context all of 2015."
Adele's new disc was released on November 20, with the Hello single out a month earlier.
Besides sales, MTV considers streams, impact on pop culture and an artist's contact with fans through social media in its decision. Adele is relatively low key in social media and, thus far, hasn't made songs from 25 available for streaming through sources like Spotify.
Fetty Wap "just absolutely came out of nowhere and blew us away", Ditzian said. MTV is impressed with how the rapper, born Willie Maxwell in Paterson, New Jersey, wasn't held back by a disability. Fetty Wap lost his left eye to glaucoma as a youngster.
Adele's Hello was everywhere for the past month, but ranked No. 2 to Drake for best song. Hotline Bling was "inescapable in a very good way", Ditzian said.
Rounding out MTV's Top Five best songs were Can't Feel My Face by The Weeknd, Lamar's Alright and Shut Up & Dance by Walk the Moon.
MTV said the best movies of 2015 were Furious 7, Straight Outta Compton and Dope.
Gigi Gorgeous was MTV's first-ever social media star of the year.
- AP