Athalia japonica (Klug, 1815) is a significant insect pest of turnips in Korea. The complete mitochondrial genome of this species isolated in Korea is reported in this study, which is the first attempt to study Korean Athalia species. The circular genome is 15,662 bp in length and consists of 13 protein-coding genes, two rRNA genes, 22 tRNA genes, and an A+T-rich region. Consistent with most members of the genus Athalia, five of the tRNA genes are rearranged from the typical ground pattern of ancestral insect gene order. Phylogenetic analyses inferred from the nucleotide sequences of 25 mitochondrial genomes indicate that the Korean A. japonica is a distinct member of the genus Athalia. This study accumulates mitochondrial genome data of A. japonica from various countries, providing useful information on mitochondrial genetic differences across geographical distances in the East Asian region.