Nephrops norvegicus is a commercially valuable demersal fisheries species. Relatively little is understood about this species’ population dynamics across its distribution with previous mitochondrial and microsatellite studies failing to identify significant population-level differentiation. In this study, sequence variation in the mitochondrial (mtDNA) D-loop was analysed from samples across the distribution range, and compared with COI sequences for this species retrieved from GenBank. Analysis of a 375 bp fragment of the D-loop revealed significant genetic differentiation between samples from the North-east Atlantic and the east Mediterranean (FST = 0.107, P < 0.001). Tau (τ), theta (θ0 and θ1) and Fu's FS values suggest the species spread between 10,500 to 19,000 ybp and subsequently expanded rapidly across the Atlantic.