We present a genome assembly from an individual female Hecatera dysodea (the Small Ranunculus; Arthropoda; Insecta; Lepidoptera; Noctuidae). The genome sequence is 640.9 megabases in span. Most of the assembly is scaffolded into 32 chromosomal pseudomolecules, including the Z and W sex chromosomes. The mitochondrial genome has also been assembled and is 15.4 kilobases in length. Gene annotation of this assembly on Ensembl has identified 12,213 protein coding genes.