Oil-well cementing is the process of installing a cement layer to the annular space between the well-bore and casing. There are two principal operations involved in well cementing; primary cementing and remedial cementing. The aim of cementing is to keep intact zonal separation and protect the casing itself. The remedial cementing operation involves either squeeze cementing or plug cementing. At present, Ordinary Portland Cement (OPC) is widely used as oil well cement. However, it is indicated that the implementation of OPC is generating a large volume of greenhouse gases. It is being generalized that 1 tonne of OPC produces one tonne of CO2. To reduce the emission of CO2, researchers have suggested replacing the OPC with the kind of binders showing similar performance. For example, waste materials, i.e., fly ash, silica fumes, blast furnace slag, and rice husk, have shown great potential as cement replacement materials. For the last few years, geopolymer cement is gaining attention as an alternative to OPC. It offers many advantages over traditional cementing technology. Geopolymer cement can be used to entirely or partly replace OPC as it depends on industrial by-products. Geopolymer binders showed significant improvements in the rheological and mechanical properties of the blend. This course will provide an overview of the geopolymer binders (mix design philosophy, fresh slurry characteristics, rheology, mechanical properties, and durability aspects).