This paper provides a comprehensive review of the synthesis kinetics and formation mechanism of geopolymers. Geopolymers are synthesized through alkali or acid activation of aluminosilicate materials, such as metakaolin, fly ash, and ground granulated blast furnace slag (GGBFS). The review critically examines various mechanistic tools and phenomenological models used to study the geopolymerization kinetics and formation mechanisms. Mechanistic tools like Environmental Scanning Electron Microscopy (ESEM), in situ Energy Dispersive X-ray Diffractometry (EDXRD), Isothermal Conduction Calorimetry (ICC), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), and Nuclear Magnetic Resonance (NMR) have been employed to provide insights into the geopolymerization process. Phenomenological models such as the John–Mehl–Avrami–Kolmogorov (JMAK) model, modified Jandar model, and exponential and Knudson linear dispersion models have also been used to describe the kinetics and mechanisms. The formation mechanism of geopolymers is typically divided into three to four stages: dissolution of raw materials, polymerization of silica and alumina, condensation, and reorganization. The Si/Al ratio above the Si/Al ratio of reactants is more suitable and increases the rate or degree of reaction, leading to higher compressive strength geopolymer. The Na/Al ratio of 1 is also noted as optimal for producing geopolymer with good mechanical properties. The paper discusses the limitations of current techniques and the need for new methods to overcome these limitations and obtain more detailed information about all types of geopolymers. It also highlights the importance of understanding the synthesis kinetics and formation mechanisms for optimizing the properties of geopolymer materials. The review includes over 150 studies on geopolymers, with a focus on the kinetics and mechanisms of geopolymerization. It covers the introduction of raw materials, critical reviews of kinetics and mechanisms, and factors affecting these processes. Future perspectives and challenges in the field are also discussed.This paper provides a comprehensive review of the synthesis kinetics and formation mechanism of geopolymers. Geopolymers are synthesized through alkali or acid activation of aluminosilicate materials, such as metakaolin, fly ash, and ground granulated blast furnace slag (GGBFS). The review critically examines various mechanistic tools and phenomenological models used to study the geopolymerization kinetics and formation mechanisms. Mechanistic tools like Environmental Scanning Electron Microscopy (ESEM), in situ Energy Dispersive X-ray Diffractometry (EDXRD), Isothermal Conduction Calorimetry (ICC), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), and Nuclear Magnetic Resonance (NMR) have been employed to provide insights into the geopolymerization process. Phenomenological models such as the John–Mehl–Avrami–Kolmogorov (JMAK) model, modified Jandar model, and exponential and Knudson linear dispersion models have also been used to describe the kinetics and mechanisms. The formation mechanism of geopolymers is typically divided into three to four stages: dissolution of raw materials, polymerization of silica and alumina, condensation, and reorganization. The Si/Al ratio above the Si/Al ratio of reactants is more suitable and increases the rate or degree of reaction, leading to higher compressive strength geopolymer. The Na/Al ratio of 1 is also noted as optimal for producing geopolymer with good mechanical properties. The paper discusses the limitations of current techniques and the need for new methods to overcome these limitations and obtain more detailed information about all types of geopolymers. It also highlights the importance of understanding the synthesis kinetics and formation mechanisms for optimizing the properties of geopolymer materials. The review includes over 150 studies on geopolymers, with a focus on the kinetics and mechanisms of geopolymerization. It covers the introduction of raw materials, critical reviews of kinetics and mechanisms, and factors affecting these processes. Future perspectives and challenges in the field are also discussed.