Arion vulgaris Moquin-Tandon, 1855 is amongst the fastest-spreading terrestrial slugs Europe-wide. In recent years, it has been recorded in Canada, Mexico and continues to expand eastwards into Eurasia. Renowned for its high invasiveness, combatting its swift spread creates significant challenges in organising effective preventative measures. This study presents the first record of Arion vulgaris from Armenia, which is the second record of this species' invasion of the Caucasus. In 2022, a substantial population of A. vulgaris was observed close to the City of Stepanavan, which is also the first record in Armenia of the family Arionidae. How the species was introduced to Armenia remains unknown. Identification of Arion vulgaris was conducted, based on external and genital morphology and mitochondrial CO1 (cytochrome c oxidase subunit 1) gene sequencing, revealing notable similarities with Central European clades. Our results confirm the introduction and distribution of A. vulgaris to Armenia. Invasion of such species into Armenia will require additional monitoring and would be aided by further research on Armenia’s mollusc fauna in the future.