Objective:  To assess whether a relationship existed between the T102C polymorphism of 5‐HT2A receptor gene and temporomandibular dysfunction.Methods:  Sixty‐three patients with temporomandibular dysfunction, and 54 healthy volunteer controls were included in the study. Molecular analysis of the T102C polymorphism of the 5‐HT2A receptor gene was performed using PCR technique.Results:  The C/C genotype was over represented in the patients whereas T/T genotype was over represented in the controls (P < 0.05). The genotype distribution of the patients who had temporomandibular dysfunction was not different than those who did not have temporomandibular dysfunction (P > 0.05).Conclusion:  The T102C polymorphism may be involved in the etiology of temporomandibular dysfunction. The overrepresentation of the C/C variant of 5‐HT2A receptor gene in temporomandibular dysfunction suggests a possible role of the serotonergic system in this disease, particularly at the receptor level.