Maria João (born Maria João Monteiro Grancha June 27, 1956, Lisbon, Portugal) is a Portuguese jazz singer.

She is known for her vocal flexibility and improvisational skills. While typically lumped with the jazz moniker, her music incorporates an eclectic mix of various folk / ethnic musics, modern jazz, and the avant-garde. Depending on the thematic slant of a release, she has approached electronica, symphonic and other genres as well.

Although her main collaborator is Portuguese pianist Mário Laginha, she has worked with many topline musicians throughout her career, including Manu Katche, Trilok Gurtu, Bobby McFerrin, Wolfgang Muthspiel, Joe Zawinul and Kai Eckhardt.