In enzymology, a ribitol-5-phosphate 2-dehydrogenase (EC 1.1.1.137) is an enzyme that catalyzes the chemical reaction

D-ribitol 5-phosphate + NAD(P)+ ${\displaystyle \rightleftharpoons }$ D-ribulose 5-phosphate + NAD(P)H + H⁺

The 3 substrates of this enzyme are D-ribitol 5-phosphate, NAD⁺, and NADP⁺, whereas its 4 products are D-ribulose 5-phosphate, NADH, 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-ribitol-5-phosphate:NAD(P)⁺ 2-oxidoreductase. This enzyme is also called dehydrogenase, ribitol 5-phosphate. This enzyme participates in pentose and glucuronate interconversions.

• Glaser L (April 1963). "Ribitol-5-phosphate dehydrogenase from Lactobacillus plantarum". Biochimica et Biophysica Acta. 67: 525–30. doi:10.1016/0006-3002(63)91863-8. PMID 13948358.