In view of global warming, the reduction of greenhouse emissions has become a central topic for the transportation sector. In this context, the development of lightweight metals and their composites is attracting attention for structural applications. Nanoparticle reinforced metal composites are a promising solution due to their potentially excellent mechanical properties and low density. However, experimental results fall short of the theoretical predictions. The reinforcing mechanisms acting in nanoparticle composites are not yet well understood. The well-understood strengthening mechanisms for metal composites are load transfer, Orowan strengthening, grain refinement and thermal mismatch. However, those mechanisms were formulated for micrometre-sized particles and therefore have certain limitations when applied to nano-sized reinforcements. In this paper, we looked into using different nanoparticles in lightweight metal matrix. Both experimental and theoretical results were compared to gain a better understanding on the influence of difference nanoparticles and the potential mechanisms.