In enzymology, a tau-protein kinase (EC 2.7.11.26) is an enzyme that catalyzes the chemical reaction Thus, the two substrates of this enzyme are ATP and tau protein, whereas its two products are ADP and O-phospho-tau-protein.

This enzyme belongs to the family of transferases, specifically, those transferring a phosphate group to the sidechain oxygen atom of serine or threonine residues in proteins (protein-serine/threonine kinases).

The systematic name of this enzyme class is ATP:[tau-protein] O-phosphotransferase.

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 2JDO, 2JDR, and 2UW9.

Human genes encoding proteins with Tau-protein kinase activity include: