Sulfite reductase (NADPH) (, sulfite (reduced nicotinamide adenine dinucleotide phosphate) reductase, NADPH-sulfite reductase, NADPH-dependent sulfite reductase, H<sub>2</sub>S-NADP oxidoreductase, sulfite reductase (NADPH<sub>2</sub>)) is an enzyme with systematic name hydrogen-sulfide:NADP<sup>+</sup> oxidoreductase. This enzyme catalises the following chemical reaction:
Sulfite reductase is an iron flavoprotein (FAD and FMN).