The World Register of Marine Species (WoRMS) is an authoritative and comprehensive list of marine organism names, including information on synonyms. It is managed by taxonomic experts, not database managers, with each taxonomic group represented by an expert who oversees the content and ensures information quality. WoRMS includes valid species names, synonyms, vernacular names, and additional data such as literature and biogeographic information. It also contains higher classifications, linking each scientific name to its parent taxon. The classification is a compromise between established systems and recent changes, aiming to aid data management rather than suggest taxonomic opinions. WoRMS is recognized as an international standard for marine taxonomic information and is integrated into various European and international initiatives, such as LifeWatch, EMODnet, (Eur)OBIS, and GBIF. The WoRMS web portal provides functionalities like taxonomic data quality control through web-based services, allowing users to compare their species list with the standard WoRMS list. This enables access to the most recent and up-to-date information. More information can be found at www.marinespecies.org. Appeltans et al. (2012) discuss the magnitude of global marine species diversity in Current Biology.The World Register of Marine Species (WoRMS) is an authoritative and comprehensive list of marine organism names, including information on synonyms. It is managed by taxonomic experts, not database managers, with each taxonomic group represented by an expert who oversees the content and ensures information quality. WoRMS includes valid species names, synonyms, vernacular names, and additional data such as literature and biogeographic information. It also contains higher classifications, linking each scientific name to its parent taxon. The classification is a compromise between established systems and recent changes, aiming to aid data management rather than suggest taxonomic opinions. WoRMS is recognized as an international standard for marine taxonomic information and is integrated into various European and international initiatives, such as LifeWatch, EMODnet, (Eur)OBIS, and GBIF. The WoRMS web portal provides functionalities like taxonomic data quality control through web-based services, allowing users to compare their species list with the standard WoRMS list. This enables access to the most recent and up-to-date information. More information can be found at www.marinespecies.org. Appeltans et al. (2012) discuss the magnitude of global marine species diversity in Current Biology.