Determining the kinetics of biomass degradation by thermogravimetry is complex due to the existence of numerous parallel and consecutive reactions. The individual use of models available in the literature has limitations regarding the applicability of the data due to high adjustment errors or lack of process information. Thus, a new procedure was proposed to determine the degradation kinetics of sisal residue, at heating rates of 20–80 ℃/min and inert atmosphere. First, the reaction order was determined by the fit model for each heating rate, resulting in approximate values. Then, the activation energy and the pre-exponential factor were determined by free models (Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, and Friedman). These models were validated from the experimental data of conversion and temperature, together with the calculated kinetic parameters. Friedman’s model was the best fit. Finally, the errors obtained are compatible with those in the literature, indicating that this procedure can be used in kinetics involving biomass pyrolysis.