The urohyal is incorporated within the hyoid and branchial arches and performs a significant role in the mouth opening-closing mechanism of fishes, and is considered a synapomorphy of teleostean fishes. Morphological variation of the urohyal, in terms of size and shape parameters, can allow species identification. Morphology of the urohyal in 49 species belonging to 43 genera and 29 families from the Persian Gulf and from the Oman Sea were compared using size and shape measurements. The results examine the suitability of using the urohyal morphology in differentiating fish species from this region; highlighting the taxonomic value of the urohyal, which until now, had been studied little in terms of use as a diagnostic feature in the classification of teleosts.