We present a genome assembly from an individual femaleMicropterix aruncella(the White-barred Gold; Arthropoda, Insecta, Lepidoptera; Micropterigidae). The genome sequence is 1,079 megabases in span. Most of the assembly is scaffolded into 31 chromosomal pseudomolecules, including the assembled Z sex chromosome. The mitochondrial genome has also been assembled and is 15.0 kilobases in length.