Symptoms of Eustachian tube dysfunction are frequent and multiple. Therefore, clear definitions and diagnostic criteria are important in order to achieve appropriate patient flow. So far, there has been a lack of consensus on this subject, but the proposed definitions and diagnostic criteria in this review may aid to achieve this. Tubomanometry is a diagnostic tool to evaluate Eustachian tube function, and balloon dilation of the Eustachian tube can be a helpful treatment in patients with Eustachian tube dysfunction.