Nanoparticles can be used as fillers to reinforce polymers, forming nanocomposites with better thermomechanical properties than composites with macrosized fillers. Furthermore, the addition of nanoparticles may influence the curing behavior of the polymer matrix during processing. In this study, the effect of various loadings of alumina or silica nanoparticles on the cure kinetics of bisphenol E cyanate ester (BECy) is investigated by differential scanning calorimetry (DSC). Alumina nanoparticles are shown to have a catalytic effect on the cure of BECy. The greater catalytic effect of alumina nanoparticles, compared with silica, is attributed to the increased number of hydroxyl groups on the surface and the Lewis acidity of gamma-phase alumina. Kinetic parameters were obtained from dynamic DSC experiments. For an autocatalytic model of the cure process, the kinetic parameters obtained from the model suggest that the addition of alumina nanoparticles changed the cure reaction mechanism of BECy. POLYM. ENG. SCI., 50:1075-1084,2010. (C) 2009 Society of Plastics Engineers