Wildfires pose a growing threat to populated areas around the world and especially in the Mediterranean Basin. Numerous Mediterranean cities have typically developed neighbourhoods that expand into forest land in which basic aspects for an efficient WUI fire management have not been considered. In this paper, we present a holistic approach to analyse threats to metropolitan areas due to WUI fires, accounting for infrastructural, societal and ecosystems vulnerability at settlement scale. Based on design fires and the key parameters responsible of fire impact and percolation through communities of most probable WUI fire events, we define key indicators to describe how vulnerable structures are in WUI metropolitan areas. Following, urban and societal indicators are selected to account for population’s vulnerability and, finally, ecosystems potential losses are accounted by ecosystem vulnerability indicators such as ecosystem sensitivity and adaptability. We have implemented this methodology to analyse vulnerability in Barcelona WUI areas and identified those that can be more threatened in case of wildfire. Results of this study will be key to inform risk-reduction public policies, as they provide particular insights on those WUI areas within Barcelona municipality that should be prioritized along with the specific issues that should be tackled.