 Critical reception to the song was mainly positive. Heather Phares of AllMusic gave the song a favorable review, calling it a "brassy empowerment jam which sells Cyrus as an independent woman." Nick Catucci of Entertainment Weekly praised the song, describing it as folding "starry Adele-style sass and a French Montana verse into expertly inlaid dubstep wub-wubs." Mikael Wood from the Los Angeles Times praised Cyrus'vocals and compared the song to Amy Winehouse, writing "Her vocals are equally strong in the surprisingly Amy Winehouse-like' FU '." Caroline Sullivan from The Guardian deemed it one of the album's best songs, writing "FU's mix of raw heartbreak, sub-bass and scathing rhyming from French Montana is devastating." Kitty Empire from The Observer reviewed the song positively, writing "Cyrus liberates her inner Christina Aguilera in the company of rapper French Montana, blending old-time jazzy balladry, I Put a Spell on You, romantic righteousness and dubstep sub-bass." Writing for MTV, John Walker reviewed the song positively, calling it an "innovative surprisingly cabaret-friendly track" and compared it to the works of Amanda Palmer. John Murphy of musicOMH compared the song to works by Lady Gaga and called it "rather excellent." Kyle Fowle from Slant Magazine heavily praised the track while comparing it to the works of Amy Winehouse and Skrillex, writing, "Cyrus plays the femme fatale with an exaggerated Southern drawl, ready to rip into male suitors and their tired pick-up lines." Catriona Wightman of Digital Spy speculated it to be inspired by Cyrus' former fiancé Liam Hemsworth and deemed it the best song of the album.
