The class Arachnida comprises approximately 100,000 described species in 16 extant orders worldwide, with members recorded from all continents and terrestrial habitats. A few groups can even be found in marine and freshwater environments. Overall, the arachnid fauna of Iran remains relatively poorly studied; excluding the superorders Acariformes and Parasitiformes, six orders of Arachnida are currently known from the country. This work provides an updated and detailed classification of the genera of whip spiders (Amblypygi), spiders (Araneae), harvestmen (Opiliones), pseudoscorpions (Pseudoscorpi­ones), scorpions (Scorpiones), and camel spiders (Solifugae) occurring in Iran, along with regional and global diversity figures for each taxon. According to current data, a total of 89 families, 421 genera, and 1,271 species representing these six orders are known from Iran.