Lygus (Insecta: Heteroptera: Miridae) is a Holarctic genus, and some of its representatives are important pests. Determining the Lygus species identity and their interrelationships is challenging. Our study aimed to delimit five trans-Palearctic species of this group: L. gemellatus, L. pratensis, L. punctatus, L. rugulipennis and L. wagneri. We implemented analyses of morphological characters, morphometrics, cytochrome c oxidase subunit I (COI) and 16S rRNA sequences. The results showed that those species could be delimited using morphology and most species pairs were different in morphometrics. Both COI and 16S rRNA were useful for species identification. Resulting phylogenetic trees contained two highly supported clades. One clade included species known from the Palearctic only, the other clade contained species with Nearctic and Holarctic distribution. Species were mostly poorly supported or non-monophyletic. Molecular species delineation approaches yielded results that generally did not correspond to the morphologically delimited species.