Guillaume-Gabriel Nivers (ca. 1632, Paris – 13 November 1714) was a French organist, composer and theorist. His first livre d'orgue is the earliest surviving published collection. with traditional French organ school forms. Nivers's other music is less known; however, his treatises on Gregorian chant and basso continuo are still considered important sources on 17th century liturgical music and performance practice. He was born into a prosperous family: his father was farmer to the bishop. Nothing is known of his early years or his musical training except that he may have received a degree from the University of Paris. In the early 1650s Nivers became organist of Saint-Sulpice, a post he would retain until 1702.
He had an illustrious career. In 1678 he was chosen as one of the four organists of the Chapelle Royale—an ensemble of musicians who performed sacred music for the king. The other three organists were Nicolas Lebègue, Jacques Thomelin and Jean Buterne. Nivers only resigned late in life, in 1708, and was succeeded by Louis Marchand. This prestigious post was followed by another in 1681, when the composer succeeded Henri Dumont as master of music to the queen. Finally, in 1686 Nivers was in charge of the music at the Maison Royale de Saint-Louis in Saint-Cyr-l'École. He was highly regarded as organist and composer but also as a music theorist.