The importance of kinetic chain length on termination kinetics has been investigated in cross-linking free radical polymerizations both experimentally and using a kinetic model. The model differs from previous multivinyl polymerization models via incorporation of chain length dependent termination (CLDT) kinetics. Experimentally, kinetic chain length distributions were manipulated, and the impact these changes have on the relationship between polymerization rate, R-p, and initiation rate, R-i, was examined over the entire conversion range for both dimethacrylate and diacrylate polymerizations. While the acrylate polymerization exhibits little change, the methacrylate polymerization exhibits significant deviation from the classical dependence of R-p on R-i; this dependence continuously changes throughout polymerization. Once the polymerization becomes reaction diffusion controlled, changes in R-i no longer effect the kinetics. The transition from chain length dependent to independent kinetics is predicted when CLDT is incorporated, thus predicting polymerization kinetics more accurately over a range of polymerization conditions.