Background: Eustachian tube dysfunction (ETD) presents a complex diagnostic challenge in otolaryngology, compounded by its multifaceted nature and overlapping symptoms with chronic nasal disease. This article examines the intricacies of ETD diagnosis, emphasising the necessity for a consensus on diagnostic procedures. Methods: A review of the literature was performed through the OVID research tool in the Pubmed/Medline databases to identify relevant articles that discuss eustachian tube dysfunction diagnostics as well as its correlation with chronic nasal disease. Results: The literature review harvested 201 articles, and only 51 of them were included in the full text review. A consensus statement was identified on eustachian tube dysfunction, function and diagnostics. It appears that there is significant variability in the diagnostic tools used to identify eustachian tube dysfunction. The main diagnostic approaches used are tympanometry, tubomanometry and sonotubometry, combined with the Patient-Reported Outcome Measure ETDQ-7 questionnaire to support the diagnosis of the condition. Nasal pathology is mostly absent from the retrieved studies, while ear pathology is more commonly mentioned in the current literature. Conclusions: There is no gold standard diagnostic tool to determine the presence of eustachian tube dysfunction. Further discussion, large multicentre studies and focused research are required to achieve a consensus on a diagnostic approach. The authors suggest a diagnostic pathway that combines subjective and objective diagnostic tools to determine the presence of eustachian tube dysfunction. This pathway is simple and can be used in district ENT departments, highlighting the nasal pathology relevance to ETD.