Abstract: Mouth protector device with tongue depressor, comprising a first cover (1) for protecting the lip and the teeth of the upper jaw and a second cover (2) for protecting the lip and the teeth of the lower jaw, both covers being connected and articulated in relation to each other by an opening and locking regulator (3), which holds the patient's mouth open for the introduction of exploration or operating instruments through the oral cavity, wherein the second cover (2) has a through groove (4) for the insertion of a semi-rigid tongue depressor (5) which depresses and holds back the tongue. The first (1) and second (2) covers further comprise side extensions (6) for protecting the row of premolars and molars and at least one tape (7) for connecting the rear ends thereof, said tape passing around the rear part of the patient's head, in order to provide the device with increased stability.