"The Girl Is Mine 2008" received generally unfavourable reviews from music critics. Journalist Christopher Rees stated that will.i.am had "done a fantastic job of murdering a classic song". Rob Sheffield of Rolling Stone noted that will.i.am's production was "dumb-thug bluster" and criticized him for trying to hide the "goofy 'doggone' hook"—"the whole point of the song". Music journalist Aidin Vaziri criticized the song, stating, "[the] Black Eyed Peas rapper completely erases Paul McCartney's vocal track from the original duet to make room for himself spouting nonsense such as, 'I call her mommy and she call me papa/I'm sorry Mike, but she loves the way I rock-a.'" Stephen Erlewine of Allmusic claimed that will.i.am had turned "The Girl Is Mine" into a "hapless dance number". Kelefa Sanneh of Blender noted that "will.i.am contributes beats (why?) and rhymes (why, oh, why?) to "The Girl Is Mine 2008" ". IGN's Todd Gilchrist stated that will.i.am's "The Girl Is Mine" remix was an offense. The offense was made even more "egregious" by the insertion of his own "atonal vocal presence" in place of McCartney's.
Pitchfork Media added to the unfavourable reviews, stating of will.i.am, "He takes Macca off 'The Girl Is Mine' but decides it can't work without someone sounding like an idiot and steps manfully in himself." The Times stated that whoever thought it was a good idea for will.i.am to participate in the song ought to be "locked in a windowless cell with nothing but those songs on a continuous loop". PopMatters, however, praised Thriller 25 and the remix of "The Girl Is Mine". They wrote, "Any album good enough to make you forgive (although maybe not forget) a song as bad as the Paul McCartney duet 'The Girl is Mine' has got to be damn good." They added that will.i.am had put a "breezy spin" on the track and that the song's omission of McCartney did not suffer because of it.