Jean-Adam Guilain (c. 1680 – after 1739) was a German organist and harpsichordist who was mostly active in Paris during the first half of the eighteenth century. A single collection of organ pieces (Pièces d'orgue pour le Magnificat sur les huit tons différents de l'église) was published in 1706 in two volumes, of which only one is now extant. The full collection included eight suites of pieces for use with the Magnificat, one suite for each church mode. Each suite contained seven short movements that were to alternate with the vocal parts of the liturgy.