Guy XIII de Laval, born Jean de Montfort, (1385- 14 August 1414, Rhodes) was seigneur of Laval and of Kergorlay. He was the son of Raoul IX de Montfort and Jeanne de Kergorlay.
Guy inherited the Laval title through his marriage on 22 January 1404 to Anne de Laval. As daughter and sole heir to Guy XII de Laval, Anne was "dame de Laval", and one of the conditions of the marriage was that any children born to it would bear the name and arms of the House of Laval. (The same condition had already been applied to the marriage of Emma de Laval with Mathieu II de Montmorency.) Nevertheless, Jean de Montfort renounced the name and title he had been born with to take up the name of Guy XIII de Laval, better to associate himself with his wife Anne's power. From the couple were descended several bishops and the greatest seigneurs of Brittany.[1] Guy and Anne had 5 children:
Guy XIII died of plague on his return from a pilgrimage to the Holy Land.