BACKGROUND Uridine diphosphate‐glucuronosyltransferases (UGTs), as multifunctional detoxification enzymes, play important roles in the biotransformation of various compounds. However, their roles in insecticide resistance are still unclear. This study presents a genome‐wide identification of the UGTs in diamondback moth, Plutella xylostella (L.), a notorious insect pest of cruciferous crops worldwide. The possible roles of these UGTs in insecticide resistance were evaluated. RESULTS A total of 21 putative UGTs in P. xylostella were identified. Quantitative real‐time polymerase chain reaction (PCR)‐based analyses showed that all the UGT genes were expressed in all tested developmental stages and tissues. Bioassay results indicated that a field‐collected population (BL) was resistant to 9 of 10 commonly used insecticides, and 10 of 21 UGT mRNAs were upregulated in the BL population. Exposure to the LC50 of each insecticide affected the expression of most UGT genes. Among these, the expression levels of UGT40V1, UGT45B1 and UGT33AA4 were induced by more than five insecticides, whereas indoxacarb and metaflumizone significantly repressed the expression of most UGT genes. CONCLUSION UGTs may play important roles in the metabolism of commonly used insecticides in P. xylostella. These findings provide valuable information for further research on the physiological and toxicological functions of specific UGT genes in P. xylostella. © 2017 Society of Chemical Industry Uridine diphosphate‐glucuronosyltransferases (UGTs) belong to multifunctional detoxification enzymes superfamily. This article identified 21 UGTs genes in Plutella xylostella and investigated their possible roles in multi‐insecticides resistance.