AT-rich interactive domain 5a (Arid5a) is a member of the arid family of proteins, which contain a helix-turn-helix domain and an ability to bind to nucleic acids. Current evidence suggests that Arid5a performs dual functions as a transcription factor and an RNA-binding protein in immune, nonimmune, and/ or tumor cells depending on its cellular localization. The contribution of Arid5a to the development of inflammation, autoimmunity, and obesity through its transcriptional and posttranscriptional regulatory functions has broadly been reviewed. Recent studies have indeed revealed an association of Arid5a with cancers, including breast, pancreatic, colorectal, and lung cancers and glioma. Notably, Arid5a affects various aspects of cellular homeostasis, including invasion, metastasis, epithelial-to-mesenchymal transition, immune evasion, adipogenesis and M1-like tumor-associated macrophage (TAM)-to-M2-like TAM transition. This review aims to summarize current knowledge of Arid5a from a cancer perspective and highlights recent advances in Arid5a-related cancer research. This review may improve the understanding of Arid5a-mediated molecular mechanisms and their relevance to cancers.