Brett Manning is an American vocal coach and singer. Over the course of his career, Manning has trained many well-known music artists, including Taylor Swift, Hayley Williams, Keith Urban, Leona Lewis, Luke Bryan, Lauren Mayberry, Miley Cyrus, TJ Harris, Wes Hampton, Debby Ryan, Poppy and Rob Chapman. He has also coached several Grammy and CMA Award winners, as well as recent Broadway casts of Les Misérables, Jekyll & Hyde, and Elton John's Aida.
He was Poppy's vocal coach in 2011 during her "Moriah Poppy" era. Poppy recorded a demo for him titled "What If I", which Manning wrote with her. Both he and Poppy recorded their own version of the song. The song later appeared on Manning's album Love Justice along with "Misery", another song he wrote with Poppy.