The cure kinetics of polydicyclopentadiene prepared by ring-opening metathesis polymerization with three different concentrations of Grubbs' catalyst were examined with differential scanning calorimetry. The experimental data were used to test several different phenomenological kinetic models. The data were best modeled with a model-free isoconversional method. This analysis revealed that the activation energy increased significantly for degrees of cure greater than 60%. The catalyst concentration had a large effect on the cure kinetics.