The kinetics of the water-gas shift reaction (WGSR) over a commercial copper/zinc oxide/alumina catalyst has been studied. Experiments were carried out in an isothermal plug-flow reactor at temperatures ranging from 453 to 490 K and a pressure of 0.3 MPa. Sixteen redox and associative models were proposed to obtain rate equations to which the obtained experimental data were fitted. Both the differential reactor approach and the integral reactor approach were used in obtaining the experimental data. The discrimination between models was based on the F test. Two statistically indistinguishable Langmuir-Hinshelwood models were found to be the best models, with apparent activation energies of 57.5 and 50.1 kJ/mol. Also, experimental data were fitted to a simple power-law rate equation, resulting in partial reaction orders of 0.47, 0.72, -0.65, and -0.38 for CO, H2O, H-2, and CO2, respectively, with an apparent activation energy of 79.7 kJ/mol and high statistical significance.