The song is the first single from TRXYE, his first extended play (EP) released by a major label.

"[3] A music video to accompany the release of "Happy Little Pill" was posted by Troye Sivan, on his Vevo YouTube page.

Mike Wass from Idolator praised the song, and said: "'Happy Little Pill' is a surprisingly mature (and dark) pop anthem.

"[5] Abby Abrams from TIME praised the lyrics and production of the song, and commented: "'Happy Little Pill' seems primed to move the teen into the big leagues, with melancholy lyrics and a downtempo electronic sound that give off a world-weary vibe.

"[6] Platform called the single "an infectious and brooding synth-pop song which is sure to take over dancefloors across the world" and praised its "profound lyricism.