ABSTRACTTranscription factor aryl hydrocarbon receptor (AhR) can enhance insect resistance to insecticides by regulating the detoxification metabolic network. Our previous studies have confirmed that overexpression of cytochrome P450 monooxygenases (P450s) and glutathione S-transferases (GSTs) are both involved inlambda-cyhalothrin resistance inCydia pomonella. In this study, we report that AhR regulates GSTs thus conferringlambda-cyhalothrin resistance inC. pomonella. Spatiotemporal expression patterns indicated thatAhRgene ofC. pomonella(CpAhR) was highly expressed in the Malpighian tubules of larvae. Moreover, the expression ofCpAhRwas induced bylambda-cyhalothrin exposure and was up-regulated in alambda-cyhalothrin-resistant population. RNA interference (RNAi) of the expression ofCpAhRcould effectively decrease the relative expression level ofCpGSTe3and enzyme activity of GSTs, but not P450s, further reducing the tolerance of larvae tolambda-cyhalothrin. Furthermore, β-naphthoflavone (BNF), a novel agonist of AhR, can effectively increase the expression ofCpAhRand the activity of the GSTs enzyme, resulting in the enhancement of larvae tolerance tolambda-cyhalothrin. These results demonstrate thatlambda-cyhalothrin exposure can effectively activate the expression ofCpAhRand increase GSTs enzyme thus leading to the development of resistance tolambda-cyhalothrin, which enriches the theory of insecticide resistance regulation inC. pomonella.