Theodoor van Loon (1581 or 1582, in Erkelenz – 1649, in Maastricht) was a Flemish Baroque painter.

Theodoor van Loon traveled twice to Italy, from 1602 to 1608 and from 1628 to 1629. He is known as a follower of Caravaggio.

Together with Wenzel Coebergher he completed commissions for Albert VII, Archduke of Austria and his wife Infanta Isabella Clara Eugenia of Spain. He also completed commissions for churches in the region of Brussels, and made an altarpiece for the Basilica of Our Lady of Scherpenheuvel (Mariataferelen, 1623–28).

He was friends with Erycius Puteanus, a professor from the University of Leuven.

According to Houbraken, his paintings show that he spent his training in Italy.^[1]

• Lamentation of Christ, between 1582 and 1660, for Scherpenheuvel Basilica
• The Adoration of the Shepherds, 1620s, Museum of Fine Arts, Boston^[2]
• The Adoration of the Shepherds, Royal Museums of Fine Arts of Belgium
• The Martyrdom of Saint Lambert, ca. 1616–1617, Royal Institute for Cultural Heritage
• Assumption of Mary, Royal Museums of Fine Arts of Belgium