Louis Couperin (c.1626–1661) was a French Baroque composer who made significant contributions to the development of Baroque keyboard music. A skillful harpsichordist, organist, and gambist, he was one of the founders of the French harpsichord school and invented the genre of unmeasured prelude for harpsichord. He and his nephew, François Couperin (François le Grand), were the most renowned members of the Couperin family. None of Louis Couperin's works were published during his lifetime.