In enzymology, a L-seryl-tRNASec selenium transferase (EC 2.9.1.1) is an enzyme that catalyzes the chemical reaction Thus, the two substrates of this enzyme are L-seryl-tRNASec and selenophosphate, whereas its two products are L-selenocysteinyl-tRNASec and phosphate.

This enzyme belongs to the family of transferases, specifically those transferring selenium-containing groups selenotransferases.

The systematic name of this enzyme class is selenophosphate:L-seryl-tRNASec selenium transferase.

This enzyme participates in selenoamino acid metabolism.

It employs one cofactor, pyridoxal phosphate.