Chlorine gas is commercially produced by Chlor-alkali process on an industrial scale using dimensionally stable anode (DSA) made of RuO2/TiO2 and the reaction is called Chlorine evolution reaction (CER). While noble metal-based CER catalysts are effective, they are expensive and not environmentally friendly. Therefore, there is a need to develop low-cost and highly selective CER electrocatalysts. This chapter provides an overview of recent advancements in CER electrocatalysts, along with the challenges faced and future opportunities. A brief history of the Chlor-alkali process and the commercial aspects of the chlorine gas industry are also discussed. The scope of the CER catalysts includes earth-abundant metal-based catalysts, carbon-based catalysts, and other hybrid nanoelectrocatalysts. A brief summary of their performance is tabulated and discussed in detail.