Grapevine (Vitis vinifera) glycosyltransferase 5 (VvGT5) is a UDP‐glucuronic acid:flavonol‐3‐O‐glucuronosyltransferase that catalyses the 3‐O‐specific glucuronosylation of flavonols using UDP‐glucuronic acid as a sugar donor to produce flavonol 3‐O‐glucosides, which are important bioactive phytochemicals. Recombinant VvGT5 expressed in Escherichia coli cells was purified and crystallized by the sitting‐drop vapour‐diffusion method. A full set of X‐ray diffraction data was collected to 2.2 Å Bragg spacing from a single crystal using a synchrotron‐radiation source. The crystal was hexagonal, belonging to space group P6122, with unit‐cell parameters a = b = 102.70, c = 535.92 Å. The initial phases were determined by the molecular‐replacement method.