An oral device for improving airway patency comprises a tongue constraint and a negative pressure source. The tongue constraint engages the patient's tongue to maintain a clear region below the palate in an oral cavity. By applying a negative pressure in the clear region, an airway behind the soft palate or tongue of the patient can be maintained. The tongue constraint is usually connected to an anchor. The anchor may be held between the patient's teeth or may engage the inferior surface of the palate. Another oral device for improving airway patency comprises a lateral tongue structure and a negative pressure source.