Circular RNAs (circRNAs) play a crucial role in modulating the TGF-β signaling pathway in cancer progression and metastasis. This review explores the intricate relationship between circRNAs and the TGF-β signaling pathway, highlighting their regulatory functions in cancer biology. CircRNAs, once considered byproducts of splicing errors, have emerged as sophisticated regulators of gene expression due to their unique circular structure, which makes them resistant to exonucleases. They can modulate TGF-β signaling through various mechanisms, including acting as miRNA sponges, directly interacting with TGF-β pathway components, and influencing key cellular processes such as epithelial-mesenchymal transition (EMT), migration, and cell proliferation. CircRNAs have shown promise as diagnostic and prognostic biomarkers and potential molecular targets for cancer therapy. The study also highlights the dual role of TGF-β signaling in cancer, functioning as a tumor suppressor in early stages and a promoter in later stages. The interplay between circRNAs and TGF-β signaling has significant implications for therapeutic strategies, with precision medicine approaches aiming to modulate the pathway based on the specific context of the tumor. The review discusses the roles of circRNAs in various cancers, including breast, colorectal, pancreatic, gastric, lung, hepatocellular, oesophageal squamous cell, and bladder cancers, emphasizing their impact on tumor progression, metastasis, and therapeutic interventions. The findings underscore the importance of circRNAs in cancer biology and their potential for developing novel therapeutic strategies.Circular RNAs (circRNAs) play a crucial role in modulating the TGF-β signaling pathway in cancer progression and metastasis. This review explores the intricate relationship between circRNAs and the TGF-β signaling pathway, highlighting their regulatory functions in cancer biology. CircRNAs, once considered byproducts of splicing errors, have emerged as sophisticated regulators of gene expression due to their unique circular structure, which makes them resistant to exonucleases. They can modulate TGF-β signaling through various mechanisms, including acting as miRNA sponges, directly interacting with TGF-β pathway components, and influencing key cellular processes such as epithelial-mesenchymal transition (EMT), migration, and cell proliferation. CircRNAs have shown promise as diagnostic and prognostic biomarkers and potential molecular targets for cancer therapy. The study also highlights the dual role of TGF-β signaling in cancer, functioning as a tumor suppressor in early stages and a promoter in later stages. The interplay between circRNAs and TGF-β signaling has significant implications for therapeutic strategies, with precision medicine approaches aiming to modulate the pathway based on the specific context of the tumor. The review discusses the roles of circRNAs in various cancers, including breast, colorectal, pancreatic, gastric, lung, hepatocellular, oesophageal squamous cell, and bladder cancers, emphasizing their impact on tumor progression, metastasis, and therapeutic interventions. The findings underscore the importance of circRNAs in cancer biology and their potential for developing novel therapeutic strategies.