"I Love You" (stylized in all lowercase) is a song by American singer Billie Eilish from her debut studio album, When We All Fall Asleep, Where Do We Go? (2019). Eilish co-wrote the song with her brother Finneas O'Connell, who also handled production. As the 13th track on the album, "I Love You" is an acoustic ballad accompanied by various plane-related noises, where Eilish's lyrics describe the resistance to falling in love with someone.
The song received mainly positive reviews from music critics, several of whom praised the music and lyrical content. For promotional purposes, "I Love You" was performed live during Eilish's 2019 When We All Fall Asleep Tour and her 2020 Where Do We Go? World Tour. When the album was released, the song reached number 53 on the US Billboard Hot 100 and charted in several other countries. It was certified platinum in the United States and Canada by the Recording Industry Association of America (RIAA) and Music Canada (MC), respectively.