We present a genome assembly from an individual male Agriphila tristella (the common grass-veneer; Arthropoda; Insecta; Lepidoptera; Crambidae). The genome sequence is 802 megabases in span. Most of the assembly (99.83\%) is scaffolded into 23 chromosomal pseudomolecules with the Z sex chromosome assembled. The mitochondrial genome was also assembled and is 15.3 kilobases in length.