Manuchar I Dadiani (Georgian: მანუჩარ I დადიანი; died 1611) was Prince of Mingrelia, of the House of Dadiani, from 1590 until his death. A younger son of Levan I Dadiani, he succeeded on the death of his elder brother, Mamia IV Dadiani.
Manuchar ruled over Mingrelia, in western Georgia, in a period of continuous anarchy in the successor states of the former kingdom of Georgia. Manuchar continued his predecessors' efforts to extend the Dadiani's influence over the kingdom of Imereti, Mingrelia's nominal suzerain. He fought off an invasion led by King Simon I of Kartli, who sought to reunite all of Georgia under his aegis, and secured his protégé Rostom on the throne of Imereti, thereby briefly restoring relative peace in western Georgia. Manuchar died in a hunting accident and was succeeded by his son, Levan II Dadiani.