Kevin Rutherford of Billboard magazine praised the song, writing: "The result is a sun-drenched, happy-go-lucky tune, that's sure to provide Flo with a horse in the summer anthem race.. Flo's not a formidable singer, so his latest offering may lack the pop pizzazz of 'Good Feeling' and 'Wild Ones.'
Upon the release of "Whistle", many music critics commented on the song's sexually suggestive lyrics, with many claiming that the chorus is a subtle reference to oral sex.