Circular RNA, also called circRNA, is a type of widespread RNA that is mainly derived from the spliceosome, from which DNA is transcribed into messenger RNA (mRNA). CircRNAs are characterized by the formation of a covalently closed continuous loop, and they play a variety of gene regulatory roles. CircRNAs were initially thought to represent splicing errors, but an increasing amount of evidence indicates that they may play significant roles in a variety of human diseases, including cancers, cardiovascular disease, neurological disorders, and pre-eclampsia. Studies have suggested that circRNAs regulate miRNA activity that arises from miRNA-mediated sponge effects. It has been shown that CDR1as acts as a sponge for miR-7 and that a testis-specific circRNA within the sex-determining region of Y (SRY) acts as a sponge for miR-138. Because miR-7 and miR-138 modulate several oncogenes and tumor suppressor genes, the interactions between ciRS-7 and miR-7 and between SRY and miR-138 may play important roles in cancer-related pathways. Hence, currently available data suggest that circRNAs may exert significant effects on diagnoses, prognoses, and therapies in ovarian cancer.