John Sullivan for "New York Magazine" described "Lithium" as a "flawlessly crafted hit." AllMusic's Mark Demming remarked, "For all the sound and fury of Nirvana's epochal album, "Nevermind", it's significant that the album's best and most affecting song is also among the quietest. ... The liberating force of Nirvana's inspired anger was rarely more powerful than in the service of this song." "Time" music critic Christopher Farley praised the song for its "gorgeous guitar hooks," writing, "Its punk-inspired, we-couldn't-care-less ethos seemed to reflect the restless apathy some young people felt toward their times."