New faunistic and taxonomic data are provided for 27 families of Iranian spiders. Two lycosid species, Lycosa elymaisa sp. nov. (♂; Kohgiluyeh & Boyer-Ahmad, southwestern Iran) and Pardosa zagrosica sp. nov. (♂♀; Chaharmahal & Bakhtiari and Hamedan, southwestern to northwestern Iran) are described as new to science, three genera (Amaurobius C. L. Koch, 1837, Cercidia Thorell, 1869, Marilynia Lehtinen, 1967) and 19 species are recorded in Iran for the first time, and 75 new provincial records are provided for 50 species. Additionally, Sahastata sinuspersica Marusik, Zamani & Mirshamsi, 2014 is recorded for the first time from Pakistan, and the Georgian record of Neoscona theisi (Walckenaer, 1841) is rejected and attributed to Neoscona spasskyi (Brignoli, 1983). Finally, an updated list of taxa omitted from the checklist of Iranian spiders (including 38 new cases) is presented, reducing the known number of spiders in Iran to 909 species.