Currently a high potential of PP foams in automotive industries guided us for a study on foamability of blends, composite and nanocomposites of PP. In case of blends, foaming of PP/HMS PP blends and PP/crosslinked or uncrosslinked elastomer blends was studied. In general that the foam density reduced with increase of branched content for all conditions. DSC analysis of the foams which was foamed at a constant pressure and varying temperature revealed a presence of threshold foaming temperature beyond which the melting point of foams increase significantly. On the other hand, PP/elastomer blend foams, smaller particles gave better foam nucleation and homogeneous cell formation. Blends interface acted as the nucleating site for foaming and interfacial interaction of raw materials had very important role either in development in blend morphology as well as in foamability. The introduction of crosslinked elastomer into the polypropylene matrix improved the foamability of polypropylene up to a certain limit and then deteriorated. Although in PP/fiber system, incorporation of fiber increased the foamability of PP; a significant insight could be observed for the uncompatibilized and compatibilized composites in terms of polymer-fiber interaction, which eventually governed the foamability. The compatibilized composites showed lower density foams with smaller cell sizes as compared to the uncompatibilized composites. The rheological influence on the development of clay microstructure foamability of PP/clay nanocomposites was identified. With an increase in saturation time, there was a phenomenal decrease in expansion ratio of neat polypropylene due to CO2-induced crystallization which could be mitigated by the incorporation of nanoclay into the polypropylene matrix. Therefore, nanoclay could be exploited as the inhibitor of CO2-induced crystallization. The objective of introducing HNT and CNT was to facilitate the heterogeneous nucleation for foaming and improvement of melt strength of polypropylene.