Willem die Madocke maecte (c. 1200 – c. 1250;[citation needed] "William-who-made-Madoc") is the traditional designation of the author of Van den vos Reynaerde, a Middle Dutch version of the story of Reynard the Fox.
The name of the author derives from the first line of the poem, where he introduces himself as the same Willem who had previously written a work called Madoc: Willem, die Madocke maecte, Daer hi dicken omme waecte, Hem vernoyde so haerde Dat die avonture van Reynaerde In dietsche onghemaket bleven.
References to localities in the poem suggest that he lived much of his life in East Flanders, including Ghent, a town he mentions twice in his work.
[1] The only surviving Medieval text that can be attributed to Willem is the satirical narrative poem Van den vos Reynaerde.
No copies of Willem's Madoc are known to have survived, but there are references to it that suggest that the poem was widely circulated in manuscript.