Abstract Objectives: To investigate the relationship between allergic rhinitis (AR) and dental malocclusion from an otolaryngologic perspective. Design: Retrospective study. Setting: Single tertiary medical center. Participants: Patients (n=217) referred to the otolaryngology department before initiating orthodontic treatment were recruited. Main outcome measures: The frequency and severity of AR symptoms, sinonasal outcome test (SNOT-22) scores, physical examination findings, acoustic rhinometry results, and treatment modalities were retrospectively assessed. Patients with positive skin prick test findings (SPT) (n=173; orthodontic group) were compared with age- and sex-matched patients being treated for AR (AR group). Results: Total 76.5% of the enrolled patients had subjective nasal symptoms, and 93.1% patients showed abnormal physical examination findings: inferior turbinate hypertrophy (82.0%), adenotonsillar hypertrophy (31.8%) or deviated nasal septum (7.4%). The 173 (79.7%) patients with positive SPT results exhibited a significantly higher incidence of rhinorrhoea, sneezing, and inferior turbinate hypertrophy compared to those with negative SPT results. The proportion of patients who underwent pharmacological or surgical treatments was significantly higher among patients with nasal obstruction (92.0%) than among patients without nasal obstruction (36.9%). The frequency and mean visual analogue symptom scores for nasal obstruction, rhinorrhoea, and sneezing, as well as all SNOT-22 domain scores were significantly higher in the AR group than in the orthodontic group. The minimal cross-sectional area measured with acoustic rhinometry showed no significant difference between groups. Conclusion: Patients with dental malocclusion had a high SPT (+) rate and a high prevalence of structural abnormalities of the upper airway. Early intervention may prevent further progression of malocclusion.