The activation of peroxymonosulfate (PMS) by cobalt?based catalysts has the advantages of high catalytic activity, simple operation, easy recyclability, and low cost. Hence, it has attracted much attention in the field of advanced oxidation processes in recent years. This paper reviewed typical methods for the synthesis of cobalt?based catalysts, including solid phase, gas phase, and liquid phase methods. Several types of cobalt?based catalysts for PMS activation, including cobalt oxides with special morphologies, supported cobalt catalysts, and cobalt?based composite metal oxides, were summarized. The applications of these cobalt?based catalysts in environmental remediation via PMS activation were also elaborated, such as the degradation of organic dyes, endocrine?disrupting chemicals, and pharmaceutical and personal care products. Finally, the current shortcomings of cobalt?based catalysts in PMS activation were summarized, and some future research directions in this area were proposed.