Circular RNAs (circRNAs) are a class of newly discovered endogenous non-coding RNAs and are widely expressed in various mammalian tissues or cells. Compared to traditional linear RNAs, circRNAs have strong stability due to the closed-loop structures which are resistant to RNA exonuclease and terminator exonuclease mediated degradation, and can be detected in the serum, urine, saliva and other body fluids. A large number of reports have reported that circRNAs participate in various biological processes such as embryonic development of organisms and cell proliferation, differentiation, and apoptosis through the circRNA-microRNA (miRNA)-mRNA network, and are also related to the occurrence, invasion and metastasis of tumors. Recent studies have confirmed that there is dysregulation of circRNA expressions in thyroid cancer tissue. The dysregulated circRNAs participate in the occurrence and development of thyroid cancer by acting as a molecular sponge of miRNAs to regulate the expression of downstream target genes. Here, the authors based on review of the research progress of circRNAs, address the expression of circRNAs in thyroid cancer and their roles and action mechanisms in the occurrence, development and metastasis of thyroid cancer.