In the present study, the effect of dynamic vulcanization, mixing sequence, and cellulose nanocrystal (CNC) content on mechanical, rheological, and thermal properties of the polypropylene/ethylene propylene diene monomer (PP/EPDM/CNC) ternary blend-nanocomposites was investigated. Significant reduction in tensile and yield strengths occurred for the un-vulcanized PP/EPDM blend compared to PP. Vulcanization and adding CNC have compensated for the decrease in tensile and yield strengths of the un-vulcanized blend. The tensile and yield strengths of the vulcanized samples had almost a slight uptrend by adding CNC. Elongation at break for both nanocomposites types had slight changes compared to that of PP/EPDM-thermoplastic vulcanizates and all of them were approximately in the range of 600%-700%. Adding CNC before or after vulcanization had the same effect on the trend of Young's modulus and the higher the amount of CNC, the greater the increase in Young's modulus. Incorporating and increasing the amount of CNC improved the impact strength of all samples, especially when added after vulcanization. Rheological measurements showed that vulcanization of PP/EPDM resulted in frequency independence of storage modulus and a more sharp increment in Complex viscosity. Also, the more CNC content, the more dramatic changes occurred in complex viscosity, especially in DV-CNC nanocomposites. Differential scanning calorimeter analysis showed that all samples had higher crystallinity which was more significant for Dynamic vulcanization (DV)-CNC nanocomposites. Scanning electron microscope images also indicated that the addition of CNC increased fracture surface roughness for all samples ignoring their preparation sequence.