The album yielded four singles: "Couleurs" in February 2008, "Graveyard Girl" in April, "Kim & Jessie" in July and "We Own the Sky" in December. "Kim & Jessie" was placed at number 256 on Pitchfork Media's list of The Top 500 Tracks of the 2000s in August 2009.
Saturdays = Youth was met with positive reviews from most music critics. At Metacritic, which assigns a normalised rating out of 100 to reviews from mainstream critics, the album received an average score of 70, based on 29 reviews, indicating "generally favorable reviews". Andy Battaglia wrote for The A.V. Club that Saturdays=Youth "boasts a more expansive sense of space" than the band's previous albums, and that it "serves in terms of songs as much as sound design: For all the awe kindled by the effectively perfect sound in a transcendent highlight like 'Kim & Jessie,' the real triumph is that M83 uses such a setting for more simple melody and emotion than ever before." Dave Hughes of Slant Magazine gave the album four out of five stars, stating that "[a]lthough many songs still build toward walls of synth that flirt with white noise, the trademark crescendos are both leavened and deepened by being recast as textural objects and woven into lyrical pop songs." He also opined that "though analog synthesizer remains definitional of the M83's sound, they open the arrangements to include more naturalistic instrumentation as well. The approach allows this band named for a galaxy to seem more grounded, and yet more universal, than ever before." Brian Howe of Pitchfork Media noted that Saturdays=Youth 's songs "disperse in all directions: Producers Ewan Pearson and Ken Thomas spread the melodies and beats into a sound world of uncommon vibrancy and pristine clarity, mounted on a massive yet now more proportionate scale", adding that the album "meaningfully diversifies M83's catalog while retaining Gonzalez's indelible fingerprint."Drowned in Sound's Alex Denney commented that "Gonzales has taken a dive head-first into the lexicon of '80s pop culture and emerged with a clutch of winning tracks that borrow openly from any number of pin-ups of the era and glaze them in his breathy, expansive shoegaze sound his to generally winning effect." He continued, "Predictably there's a slide towards more abstracted material toward the latter half, and parts of Saturdays=Youth are all hairspray and no body, but the whole thing sweeps along with such an irrepressible mix of youthful invincibility [...] and flouncing fatalism [...] it sucks the wind right out of your cheeks before you've had chance to huff."Allmusic reviewer Heather Phares gave the album four out of five stars and concluded, "As super-stylized as its sounds and emotions are, Saturdays=Youth always seems genuine, even when it feels like its songs are made from the memories of other songs. For all of its nostalgic haze, it's some of M83's most focused music."
The album also received some mixed reviews. Dorian Lynskey, writing for The Guardian, gave the album three out of five stars and expressed that "[t]o call Saturdays=Youth derivative is to pay it a compliment, because every retro synth sounds calibrated to provide the maximum nostalgic rush—if not for your own adolescence, then at least for that of a poetic outcast in a John Hughes film", but noted that "[i]t's a shame the songwriting evaporates in a haze of rote shoe-gazing and ambient murmurs halfway through." Dan Raper of PopMatters felt that "it is a little disappointing that the point of Saturdays=Youth kind of misses the point. The more conventional 'song'-like material does have something of M83's stately grandeur but feels somewhat hollow, probably because the slow-burn's integral to the act's power." He nevertheless commented that "there are [still] plenty of moments on the disc that remind you why this pulsing, layered music is so powerful." Benjamin Boles of Canadian magazine Now believed that album is "more derivative and familiar than Anthony Gonzalez's past work as M83, which means it's more accessible but also less innovative and original. All the dreamy, ethereal glitter drowns the songs; the album overall is mostly about texture and nostalgia", while stating that "[s]urprisingly, the least pop-based tracks stand out most."Spin 's Mosi Reeves was unimpressed, writing that "[o]nly a few compelling songs, particularly the lush darkwave instrumental 'Couleurs' and the breezy shoegaze rock of 'Graveyard Girl,' emerge from the bathos. M83 needs to step out of the '80s and back into the future." Ben Hogwood of musicOMH rated the album three stars out of five and found that "M83 still show plenty of guile and in their best moments present music of hidden power and grace. But in this record they seem to become too preoccupied with their 80s tribute for that to continually shine through."
Pitchfork Media ranked Saturdays = Youth at number eight on its list of The 50 Best Albums of 2008 and at number 111 on its list of The Top 200 Albums of the 2000s. The album was also named the best album of 2008 by Drowned in Sound and Urban Outfitters.