Petra Haden (born October 11, 1971) is an American musician and singer. She has been a member of That Dog, Tito & Tarantula, and The Decemberists; has contributed to recordings by Bill Frisell, The Twilight Singers, Beck, Mike Watt, Luscious Jackson, Foo Fighters, Green Day, Weezer, The Rentals, Victoria Williams, Yuka Honda, The Gutter Twins, Sunn O))), and Cornelius. She is the daughter of the jazz bassist Charlie Haden; the triplet sister of bassist Rachel Haden (her bandmate in That Dog) and cellist Tanya Haden (married to singer and actor Jack Black) with whom she has performed as The Haden Triplets; and the sister of bassist-singer Josh Haden, leader of the group Spain.