Societal Impact Statement Genetic engineering is used to introduce new genes into plants to obtain crops withnovel traits. However, the unintended effects of genetically engineered (GE) crops onnontarget organisms—such as beneficial insects—are a topic of much concern. Weevaluate the potential unintended effects of pollen from three GE maize and sevencommercialized conventional maize lines on the ladybird beetlePropylea japonica,bycombining omics approaches with feeding assays. Our results suggest thatunintended changes caused by genetic engineering in maize pollen may not lead tobiologically relevant effects onP. japonica. Meanwhile our study provides a usefulstrategy to assess the biological impacts of genetic engineering on nontargetorganisms. Summary •The potential effects caused by the inserted traits in genetically engineered(GE) plants on nontarget organisms (NTOs) have been well assessed. However,whether the process of genetic engineering itself causes unintended changes thatgo beyond the natural variation of the crop and further poses any biologicaleffects to NTOs is still under debate. •Here, we evaluated the potential unintended effects of pollen from three GEmaize and seven commercialized conventional maize lines on the NTOPropyleajaponicaby combining omics approaches with feeding assays. •The results showed that genetic breeding indeed brought somewhatdifferences at both proteome and metabolome levels in maize pollen, althoughsuch differences were far more common in conventionally crossbredplants. Feeding experiments indicated that the changes in proteins andmetabolites caused by genetic breeding did not lead to unintended effects onthe NTOs that go beyond those measured for the conventional crossbredlines.