Producing alternative new and renewable fuel sources for future energy supply from the thermochemical conversion of solid wastes became necessary due to fossil fuel depletion and the rapid increase in the world’s energy demand. These solid wastes can be treated thermally through pyrolysis, gasification, and combustion. Understanding the thermo-kinetic behaviour of these wastes based on the thermal gravimetric analysis (TGA) is considered the most suitable technique to reveal the thermodynamics and kinetic parameters of any conversion process. Solid waste could be a mixture of materials with various physical and chemical properties, as blending wastes is an evolving technique to overcome drawbacks of single material properties, leading to a complex thermal conversion process, making the determination of the kinetic parameters and the most suitable reaction mechanism more challenging. Researchers have applied various mathematical models with different approximations to investigate the kinetic parameters based on the TGA data. According to the results of previous studies, these models provide different kinetics values for different materials under various conditions. Therefore, this work will focus on reviewing and comparing the different types of common kinetic models showing their origin, approximation, and solution. Other rarely applied models that provide accurate results will also be reviewed and compared with the common methods for the same materials and under the same experimental conditions. In addition, this work will introduce a new proposed method that allows easy and accurate determination of the activation energy and conversion of the volatiles and char of the individual component of bilateral and trilateral mixtures.