The primary focus of this study was to understand the effects of different amounts of montmorillonite nanoclay (MMT) loading on viscosity, cure behavior, reaction mechanism, and properties of diglycidyl ether of bisphenol A (DGEBA) epoxy composites. Influence of 1–3 wt.% MMT on rheological and subsequent cure behavior of SC-15 epoxy resin was studied using nonisothermal and isothermal rheometry and differential scanning calorimetry (DSC). Rheological properties were influenced by different amounts of MMT at lower shear rates prior to and during curing. Cure reaction mechanism was unaffected by different MMT concentration; however heat and activation energy of reactions increased with increasing MMT loading. Samples with 2 wt.% MMT showed highest reaction rate constant, indicative of catalytic behavior. X-ray diffraction (XRD) and transmission electron microscope (TEM) revealed mainly intercalated microstructure throughout the MMT infused epoxy composite samples irrespective of the percent loading.