Mathias de l'Obel, Mathias de Lobel or Matthaeus Lobelius (1538 – 3 March 1616) was a Flemish physician and botanist who was born in Lille, Flanders, in what is now Nord-Pas de Calais, France, and died at Highgate, London, England.
Graduating in medicine from the University of Montpellier in 1565 he practiced medicine in the low countries and England, including positions as personal physicians to two monarchs.
A member of the sixteenth century Flemish School of Botany, he wrote a series of major treatises on plants in both Latin and Dutch.
He was the first botanist to appreciate the distinction between monocotyledons and dicotyledons.