The present invention describes an improved surgical mouth gag for the exposure of the palatal and oropharyngeal region of a patient comprising a frame (2) adapted to be arranged in use around the mouth of the patient and a tongue depressor system (21, 30) insertable in the oral cavity of the patient and movable with respect to the frame (2), the tongue depressor blade (21, 30) comprising two elements articulated to each other, able to mobilise fully in a graduated way the entire tongue base both in the caudal and posterior-anterior direction. The metal arch (2) supports and anchors the aforesaid tongue depressor system, by resting on the upper premolar and molar teeth (respecting the incisors) and acts as an anterior window adapted to guarantee both optimal exposure of the palatal structures and of the isthmus of the fauces and to facilitate palatal and oropharyngeal surgery in general and that of obstructive sleep disorders in particular.