Didrik Möllerum, also Diedrich Möllerum, (1642 – c. 1702) was a Finnish painter.

Möllerum may have been born in Denmark, then later moved to Turku. He initially studied as an apprentice under the painter Jochim Neiman. He primarily painted religious-themed works and altarpieces for church commissions. One of his early documented jobs was restoration work for the Turku Cathedral after a fire in 1681. He is also known to have done some painting for the church in Raahe (1691), and the pulpit and altarpiece painting for the church in Tornio (1701).^[1] Möllerum also painted portraits of some of the church vicars. Much of his time was spent working and living in Ostrobothnia and Tornio.^[1]