We present a genome assembly from an individual female Tenthredo mesomela (the common green Tenthredo; Arthropoda; Insecta; Hymenoptera; Tenthredinidae). The genome sequence is 393 megabases in span. Most of the assembly is scaffolded into 10 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 15.6 kilobases in length. Gene annotation of this assembly on Ensembl has identified 11,086 protein coding genes.