A kinetic study of ethylene/1-hexene copolymerization is conducted with a supported metallocene catalyst in a gas-phase reactor. The investigation into the kinetics of ethylene/1-hexene copolymerization includes the effects of operational parameters such as the reaction temperature, pressure, and comonomer concentration. The large variations in gas-phase composition using only an initial charge of 1-hexene are illustrated by experiment. To remedy this, the ability to control the comonomer composition of 1-hexene online for the entire duration of the reaction is demonstrated. Online perturbation techniques are implemented to determine key kinetic parameters such as the activation energies for propagation and catalyst deactivation. From pressure perturbation results, a reaction rate order close to 1 is obtained for ethylene in the presence of 1-hexene. Finally, all the parameters obtained from the study are compared to those determined from ethylene-propylene (E-P) copolymerization.