A new species of phytoseiid mites, Neoseiulus neoagrestis sp. nov., was described based on all ontogenetic stages and extensive comparison with types/vouchers of closely related species and a thorough analysis of GenBank data. Mite specimens were collected in an area at the eastern coast of the Black Sea of Russia and cultured. Molecular barcoding revealed a close match (100–99.25%) with several unidentified COX1 sequences from Canada. Both Canadian and Russian mites reproduced sexually and had consistent morphology, including the presence of gd2 gland pores, indicating that they belong to a single species, N. neoagrestis sp. nov. The presence of gd2 gland pores distinguishes N. neoagrestis sp. nov. from a closely related, parthenogenetic species N. agrestis (Karg), which lacks gd2 gland pores. Despite having an arguably negligible morphological difference, these two species were clearly distinct by COX1 sequences (19.95–22.01% K2P distances). We studied the ontogeny of N. neoagrestis sp. nov. and provided comparison with related Neoseiulus species. Furthermore, our examination of types of N. agrestis, N. salish, and N. striatus indicated that the latter two species are potential junior synonyms of N. agrestis.