The kinetics of the transesterification reaction has been explored theoretically. A general rate equation (GRE) was obtained for kinetics modeling of transesterification at the entire time of reaction based on a three-step mechanism. It has been shown that the GRE model converts to a Second-Order (SO) model at short initial times of reaction and it converts to Pseudo-First-Order (PFO) model at short initial times of reaction and high concentration of alcohol. Also, a modified form of the Second-Order model (MSO) was derived when the reaction is spontaneous (at Delta(r) G << 0 conditions or at short initial times of reaction). The accuracy of theoretical models and our assumptions was evaluated by three sets of experimental data selected at literature. It has been shown that the accuracy of PFO, SO, and MSO models followed the order of MSO > SO > PFO at short initial times while the GRE model is a suitable kinetics model at the entire times of reaction. Also, our research, contrary to what has been reported so far in published papers, shows that pseudo-first-order and second-order models are only accurate for kinetics modeling of the transesterification reaction at short initial times of reaction. (c) 2020 Elsevier Ltd. All rights reserved.