| Dionis de Lys | |
| Order: | Conquistador of the |
| Office: | Spanish Empire |
| Birth Date: | c.1510 |
| Birth Place: | Flanders, Habsburg Netherlands |
| Death Date: | c.1560 |
| Death Place: | Asunción, Viceroyalty of Peru |
| Nationality: | Flemish |
| Occupation: | Conqueror explorer |
| Profession: | Sailor |
| Branch: | Spanish Navy |
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.
Dionis was born in Lys, County of Flanders, the son of Johannes de Lys and Barboxa de Leys. He had arrived to the Río de la Plata in the expedition of Pedro de Mendoza, together with a contingents of Flemish adventurers.
Lys traveled to Asuncion, where he formed a family, a daughter Catalina de Lys was married to Luis Alegre, also born in Flanders.