In enzymology, a mannose-6-phosphate 6-reductase (EC 1.1.1.224) is an enzyme that catalyzes the chemical reaction

D-mannitol 1-phosphate + NADP⁺ ${\displaystyle \rightleftharpoons }$ D-mannose 6-phosphate + NADPH + H⁺

Thus, the two substrates of this enzyme are D-mannitol 1-phosphate and NADP⁺, whereas its 3 products are D-mannose 6-phosphate, NADPH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. The systematic name of this enzyme class is D-mannitol-1-phosphate:NADP⁺ 6-oxidoreductase. Other names in common use include NADPH-dependent mannose 6-phosphate reductase, mannose-6-phosphate reductase, 6-phosphomannose reductase, NADP⁺-dependent mannose-6-P:mannitol-1-P oxidoreductase, NADPH-dependent M6P reductase, and NADPH-mannose-6-P reductase.

• Rumpho ME, Edwards GE, Loescher WH (1983). "A pathway for photosynthetic carbon flow to mannitol in celery leaves: Activity and localization of key enzymes". Plant Physiol. 73 (4): 869–873. doi:10.1104/pp.73.4.869. PMC 1066569. PMID 16663332.