In enzymology, a sulfite dehydrogenase () is an enzyme that catalyzes the chemical reaction
The 3 substrates of this enzyme are sulfite, ferricytochrome c, and H<sub>2</sub>O, whereas its 3 products are sulfate, ferrocytochrome c, and H<sup>+</sup>.
This enzyme belongs to the family of oxidoreductases, specifically those acting on a sulfur group of donor with a cytochrome as acceptor. The systematic name of this enzyme class is sulfite:ferricytochrome-c oxidoreductase. Other names in common use include sulfite cytochrome c reductase, sulfite-cytochrome c oxidoreductase, and sulfite oxidase. This enzyme participates in sulfur metabolism.