Epoxies are highly flammable; also, they release a significant amount of smoke and gases. This intrinsic flammable property of the epoxy (EP) matrix can be reduced by incorporating fire-retardant (FR) materials. Several chemicals are used as FRs; however, most of the chemicals are harmful to the environment. Thus, nanofillers can be suggested as FRs for EP matrices; besides, they are more environmentally friendly materials. This review aims to summarize the FR properties of different nanofillers such as organic nanoparticles (graphene, carbon nanotubes), inorganic nanoparticles (layered double hydroxide, montmorillonite’s, molybdenum disulfide), and hybrid nanoparticles (graphene/carbon nanotubes-clay hybrids). Many researchers reported that these nanoparticles could be used as an efficient FR material in EP matrices.