"Backd00r" is a song by American rapper Playboi Carti, featuring American rapper Kendrick Lamar and American singer Jhené Aiko. It was released to US rhythmic radio on October 14, 2025 as the second single from Carti's third studio album, Music. The song was written by Playboi Carti and Kendrick Lamar, alongside producers Ojivolta, Keanu Beats, Darius Rameshni, Jugraj Nagra, and Jarrod "Twisco" Morgan. The song contains a sample of "Mutual Feeling" by Beverley Knight.