Guy Coquille (1523, Decize – 1603), also called Conchyleus, was a French jurist.
He studied the humanities in the Collège de Navarre, Paris, from 1532 to 1539, and then law in Padua and Orléans. Coquille took up the practice of law in Paris in 1550, and moved to Nevers in 1559, where he worked as an advocate for the Parlement. He represented the Third Estate of his province in the States-General of 1560, 1576 and 1588, and served as procureur fiscal of the Duke of Nevers from 1571 on.
Coquille's writings were all published posthumously. They include the Institutions au droit des Francois, ou Nouvelle Conférence des Coutumes de France (1607) and the Questions et responses sur les Coutumes de France (1611). These works attempted to cover the laws of France comprehensively without respect to their origin in the common law or in Roman law, a novel approach that first emerged in the legal writing of 16th century France, and later in that of other European countries as well.