Louis de Cahusac was an 18th-century French playwright, librettist, and Freemason. He is most famous for his work with the composer Jean-Philippe Rameau. He provided the libretti for several of Rameau's operas, namely Les fêtes de l'Hymen et de l'Amour (1747), Zaïs (1748), Naïs (1749), Zoroastre, La naissance d'Osiris (1754), and Anacréon. He is also credited with writing the libretto of Rameau's final work, Les Boréades. Cahusac contributed to the Encyclopédie and was the lover of Marie Fel.