scorpions are arachnids which comprises spiders, harvestmans, mites, solpugids, whipscorpions, windscorpions and pseudoscorpions.
A more precise classification of scorpions is that they are in the Order Scorpiones of the Class Arachnida of the Sub-phylum Chelicera of Super-Phylum Arthropoda which belongs to the Kingdom Animalia.