Numerical models are helpful vehicles for understanding and describing the engineering properties of construction materials. With the rapid development of both computational capabilities and theoretical insights into chemical reactions, there have been increasing research activities around the globe and raising demands for computational methods that describe different characteristics of alkali-activated materials. In this Chapter, we summarized the collective efforts performed on modelling and simulation of alkali-activated materials in the past two decades and highlighted the most relevant results and advances in the aspects of atomistic simulation, thermodynamic modelling, kinetics modelling, microstructure simulation, and multi-scale modelling. It can be concluded that pioneering work on modelling and simulation of alkali-activated materials has been conducted with fruitful results. However, there are still deficiency gaps and challenges in modelling and simulation of alkali-activated materials, especially in comparison with PC-based materials.