Alien species are species that are introduced into an area where they are not naturally present. Some of them may exert negative ecological impacts, thus being defined as invasive. The aoudad or Barbary sheep Ammotragus lervia is a north-African ungulate commercialised and introduced for game hunting to Europe, South Africa, and America. As a generalist herbivore, the aoudad has a high capacity to adapt to new habitat conditions, possibly representing a threat to local biodiversity. We studied the aoudad population present in the Beigua Natural Regional Park in Liguria, north-western Italy. By using historical data and camera trapping data, we reconstructed the colonization process and current distribution, estimated minimum abundance, assessed population trends over the years, and investigated habitat selection and activity rhythms. Aoudads most likely escaped from a game reserve in Ponzone Municipality, Piedmont, and settled in the park at least since 2009. The minimum number alive doubled in 10 years, from 9 to 23, and the population shows an increasing trend. Aoudads showed a preference for steep, rocky and woody areas in the southern and warmer part of the Beigua massif, especially at intermediate elevations. Some observations have recently occurred in the northern part of the Park, potentially due to geographical expansion. Aoudads show mostly diurnal activity, unlike native ungulates such as roe deer Capreolus capreolus and wild boar Sus scrofa which were most active at dawn, dusk and during the night, possibly reflecting anti-predator behaviour towards wolf Canis lupus. Our results are in line with other studies, though births occurred across a wider period of time compared with native populations. As the potential ecological impacts of this alien species in the study area have never been investigated, it will be important to monitor the population and evaluate its ecological effects to provide the most appropriate management solutions.