Background: Hashimoto's thyroiditis (HT) is the most common cause of hypothyroidism in iodine-sufficient areas of the world.The pathophysiology of HT is contributed to a combination of genetic susceptibility and environmental factors. Objective: We aimed in the current study to investigate the relative expression level of hsa_circ_0007777 in patients with or without HT and to assess their associations with thyroid dysfunction. Patients and Methods: A case-control study included 70 patients with HT and 70 healthy control subjects.Anti- thyroglobulin (anti-TG), anti-thyroid peroxidase (anti-TPO) were measured. Real-Time Quantitative PCR (RT-qPCR) analyses were used to detect the relative expression levels of hsa_circ_0007777. Results: Hsa_circ_0007777 relative expression level was up regulated in patients with HT in particular patients with clinical hypothyroidism (CHT) and subclinical hypothyroidism (SCHT) compared to the euthyroid group. Andit was correlated positively with TSH, anti-TPO, and anti-TG. Moreover, linear regression analyses test revealed that in HT patients the main independent variables associated with hsa_circ_0007777 relative expression level were anti-TPO and anti-TG. Conclusion: The relative expression levels of hsa_circ_0007777 were significantly increased in patients with HT more specifically in patients with clinical and subclinical hypothyroidism.