In enzymology, a flavonol-3-O-glycoside glucosyltransferase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are UDP-glucose and flavonol 3-O-beta-D-glucosyl-(1->2)-beta-D-glucoside, whereas its 3 products are UDP, flavonol, and 3-O-beta-D-glucosyl-(1->2)-beta-D-glucosyl-(1->2)-beta-D-glucoside.
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is UDP-glucose:flavonol-3-O-beta-D-glucosyl-(1->2)-beta-D-glucoside 2-O-beta-D-glucosyltransferase.