The young star's representation confirmed the news to The Guardian, with music manager Adam Grandmaison saying the musician was taken to the hospital following a drug overdose.
Lil Peep's publicist also confirmed his death in an email to Pitchfork but did not provide a cause of death.
The rapper's manager, Chase Ortega, also broke the bad news via Twitter.
'I've been expecting this call for a year. Mother F****', he wrote to his social media followers.
Lil Peep, who was born Gustav Åhr, openly spoke about his drug use in in his lyrics.
'I suffer from depression and some days I wake up and I’m like, ‘F***, I wish I didn’t wake up,'' he told Pitchfork in an interview published in January. 'I don’t express that side of myself on social media. That’s the side of myself that I express through music. That’s my channel for letting all that s— out.'
Music industry professionals and other celebrities have taken to Twitter to mourn his loss.