In enzymology, an UTP-monosaccharide-1-phosphate uridylyltransferase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are UTP and monosaccharide 1-phosphate, whereas its two products are diphosphate and UDP-monosaccharide.
This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing nucleotide groups (nucleotidyltransferases). The systematic name of this enzyme class is . Other names in common use include UDP-sugar pyrophosphorylase, and PsUSP.