François Giroust (10 April 1737 – 28 April 1799) was a French composer. He was born in Paris, where he was the last maître of the Chapelle royale before the French Revolution. He died, aged 62, at Versailles.
After having studied at the Notre-Dame de Paris with Louis Homet (1691-1767) until 1748 and afterwards with Antoine Goulet, Giroust got appointed as maître de musique (Kapellmeister) at the cathedral of Orléans, where he stayed until 1769. He was very much appreciated by his employers. He also became the leader of the music academy of Orléans (1757-1765), which became a big yet temporary success soon after his appointment.
Two of his works won both 1st and 2nd place in a contest for composers of the Concert Spirituel, organised by the Tuileries in Paris, 1768. Because of this, he got appointed as kapellmeister at the church of the Saint-Innocents in Paris.
In 1775 he became kapellmeister at the Chapelle Royale at Versailles under Louis XVI's reign. In 1780 he got appointed as surintendant of the same chapel, a post he kept until 1792. After some financial hardships he became a concierge at the Palace of Versailles, where he died on 28 April 1799.
Giroust is well known for his many revolutionary pieces, among which the Hymne des Versaillais is the most famous. Most of his masonic work has been lost. Most of his other works have been saved by his widow Marie-Françoise de Beaumont d'Avantois, who was a singer at the same court.