Waste gasification is considered one of the most promising potential routes for the fuel gas production since it represents one of the most powerful and reliable approaches for the biomass conversion. Tar is the undesirable, but unavoidable, by-product of the gasification processes. not only does it lower the overall energy conversion efficiency, but it also leads to potential contamination and clogging problems, thus It is of paramount importance to remove it. Tar can be converted into gases by catalytic cracking, which has become a hot research topic in biomass pyrolysis and gasification technologies. Various tar cracking catalysts have been extensively studied and current advances in the study of nanomaterials have attracted wide interest for their catalytic properties compared to their bulk counterparts: in particular, the supported transition metal NanoParticles show the best catalytic characteristics for tar cracking. This work gives a comprehensive overview of the most promising nanocatalysts for tar removal reported in the litterature: it reviews the different synthesis methods and the catalytic properties of the produced nanocatalysts, thus providing useful information for the understanding of the most promising routes for an efficient conversion of biomass tar into combustible gas.