Lucas Gassel or Lucas van Gassel was a Flemish Renaissance painter and draughtsman known for his landscapes. He helped further develop and modernize the landscape tradition in Flanders. He also designed prints which were published by the Antwerp publisher Hieronymus Cock.

Little is known about the life of this artist. Born in Deurne, Netherlands, Lucas Gassel is believed to have moved to Antwerp before 1520. Here he received his artistic training. Historiographical tradition links him to the artistic milieu of Brussels, a city which he is assumed to have moved to. The influences visible in his work link him much more to the Antwerp school of painting. On the other hand, his frequent depictions of scenes at the court point to a possible stay in Brussels where the court was located.

He was a humanist and was linked with other humanists in the Low Countries. He was a friend of Dominicus Lampsonius who included him in his 1572 publication Pictorum aliquot celebrium Germaniae inferioris effigies (literal translation: Effigies of some celebrated painters of Lower Germany), a set of 23 engraved portraits of leading artists from the Low Countries who had died.