Abstract Background Praying mantises, members of the order Mantodea, play important roles in agriculture, medicine, bionics, and entertainment. However, the scarcity of genomic resources has hindered extensive studies on mantis evolution and behavior. Results Here, we present the chromosome-scale reference genomes of 5 mantis species: the European mantis (Mantis religiosa), Chinese mantis (Tenodera sinensis), triangle dead leaf mantis (Deroplatys truncata), orchid mantis (Hymenopus coronatus), and metallic mantis (Metallyticus violacea). The assembled genome sizes range from ∼2.3 to 4.2 Gb, with contig N50 size 1–109 Mb and 85%–99% of sequence anchored to chromosomes. The annotated protein-coding gene number ranges from 17,804 to 19,017, with a BUSCO complete rate of 96.7%–98.4%. We found that transposable element expansion is the major force governing genome size in Mantodea and suggest that translocations between the X chromosome and an autosome have occurred in the lineage of the family Mantidae. In addition, we found that the lineage of M. violacea has accumulated fewer substitutions than the lineages of other mantises. Furthermore, our genome-wide analyses showed that D. truncata is sister to H. coronatus compared with M. religiosa and T. sinensis, which helps resolve the phylogenic controversies of the Deroplatys genus. Conclusions The high-quality genome assemblies of the 5 mantises provide a valuable resource for evolution studies of Mantodea and genetic improvement and breeding of beneficial biological control agents.