Giacomo, or Jacob de Decker (1640, Haarlem – 1680, Rome), was a Dutch Golden Age painter.
According to Houbraken he travelled to Rome and joined the bentvueghels with the bentname Gulden Regen.
[1] He signed Abraham Genoels bentbrief on 3 January 1675.
[1][2] According to the RKD he may have been the son of the Haarlem landscape painter Cornelis Gerritsz Decker.
[2] He is known in Haarlem for his illustrations for Petrus Scriverius.