The compilation of papers on marine annelids along the coasts of Turkey together with new records of species (24 species) presented in this study yielded a total of 721 species belonging to 2 classes (Polychaeta and Clitellata), 60 families, and 352 genera. Polychaeta were represented by 705 species, Oligochaeta by 13 species, and Hirudinea by 3 species. Syllidae (119 species) and Serpulidae (56 species) were the species-rich polychaete families. The majority of annelid species were benthic (691 species), 14 species were pelagic, and 3 species (leeches) were parasitic. Thirteen polychaete species were excluded from the species inventory. The Aegean Sea had the highest number of species (559 species), followed by the Levantine Sea (459 species) and the Sea of Marmara (398 species). The hot spot areas for the species diversity were Izmir Bay, Mersin Bay, the southwest part of the Sea of Marmara, and Sinop Peninsula, where intense scientific efforts have been carried out. A total of 75 alien polychaete species were reported from the regions, 22 of which were classified as invasive species. The annelid species were generally encountered in soft substrata of the shallow-water benthic environments, whereas only 9 species were reported from depths deeper than 600 m.