<p>Some cemeteries have been recognised as biodiversity hotspots but few studies contextualise their biodiversity value across larger geographical scales. The objective of this study was to examine the diversity of vascular plant species in cemeteries in the Île-de-France region, the contribution of cemeteries to urban flora diversity and the distribution of species in cemeteries in response to an urban-rural gradient. The study was conducted in the Île-de-France region (France) with a dataset comprising 40,802 entries of vascular plants collected in 760 cemeteries between 2000 and 2021. Indicator value analysis was used to assess species’ preferences for cemeteries or other urban areas. A niche model analysis was employed in conjunction with a randomisation procedure to describe species-specific responses to the urban-rural gradient. Of the 696 spontaneous species recorded (45% of the regional flora), 593 (85%) were found to be native. Of these, 66 could be considered as species of conservation concern. Cemeteries in urban contexts harboured a pool of naturalised species rarely found in rural cemeteries. The flora of cemeteries included species rarely found in other urban areas, and particularly species that are associated with semi-natural habitats (e.g. heathlands, dry grasslands on acidic or calcareous soils, and meadows). These species, some of which are of conservation concern, were clearly associated with rural cemeteries. In conclusion, this research highlights key issues for plant biodiversity conservation in cemeteries, according to their urbanisation context, and recommendations for management to maintain their original contribution to urban biodiversity.</p>