Background Unexplained infertility (UEI) is a complex pathological condition that involves environmental and genetic factors. Hashimoto’s thyroiditis (HT) is the most common autoimmune disease in reproductive-age women. Circular RNAs (circRNAs) play a biological role in autoimmunity by regulating gene transcription. A previous study found upregulation of hsa_circ_0089172 in HT. We aimed in the current research to investigate the relative expression level of hsa_circ_0089172 in patients with HT and to assess its correlation with UEI among Egyptian women. Methods: Among 60 women with HT (35 fertile and 25 women with UEI) and 60 healthy subjects as the control group. all subjects were investigated in clinical, laboratory, and radiological. Hsa- circ- 0089172 was examined by RT-PCR. Results: There were significantly higher values of hsa_circ_0089172 in UEI group (3.4±0.26) compared to fertile group (2.34±0.33) and control group (0.91±0.216), P <0. 001. Interestingly we observed that anti-TPO and anti TG values were the independent factors associated with hsa_circ_0089172 in the prediction of UEI. hsa_circ_0089172 exposed a significant predictive value of HT, with an AUC of 0.990 (C. I=0.973-1.000), sensitivity of 91.7%, and specificity of 87.1%. Regarding the prediction of UEI among women with HT, the AUC of hsa_circ_0089172 was 0.994(C.I=0.981-1.000), a sensitivity of 94.9%, and a specificity of 89. 3%, P <0 .001 Conclusions: hsa_circ_0089172 level was upregulated in HT patients, particularly patients with UEI. Moreover, it was positively correlated with TSH, anti-TPO, and anti-TG