PVDF-based nanocomposites were fabricated through a melt-mixing process using organoclay (15A) and pristine MWNTs individually and simultaneously as nanofiller. Morphological observations revealed that MWNTs were thoroughly dispersed in the PVDF matrix and 15A was dispersed in intercalated/partially exfoliated status. The addition of 15A facilitated the formation of beta-form PVDF. By contrast, MWNTs barely changed the alpha-form formation. The MWNTs facilitated the nucleation and crystal growth of PVDF, whereas 15A facilitated the nucleation of PVDF but retarded its crystal growth. The melting behavior study demonstrated that either 15A- or MWNT-included composites possesses higher Tm° than neat PVDF, and the beta-form crystals induced in 15A-added composites led to a Tm° no less than 11 °C higher than that of neat PVDF. The addition of MWNTs increased the thermal stability of PVDF, but 15A addition caused a decrease in the thermal stability. The 1 wt.% addition of MWNTs was recognized as the starting point of the rheological percolation threshold for the prepared composites. The nanocomposites exhibited improved tensile modulus compared with neat PVDF.