Dionis de Lys or Lis (born-16th century) was a Flemish conquistador in the service of the Spanish monarchy.

He attended the first foundation of Buenos Aires by Pedro de Mendoza.

[1] Dionis was born in Lys, County of Flanders, the son of Johannes de Lys and Barboxa de Leys.

[2] He had arrived to the Río de la Plata in the expedition of Pedro de Mendoza, together with a contingents of Flemish adventurers.

[3] Lys traveled to Asuncion, where he formed a family, a daughter Catalina de Lys was married to Luis Alegre, also born in Flanders.