Nanoclays are nano-layered silicates extensively used as reinforcing fillers for composites and as catalyst support/filler material. The widely used varieties of nanoclay fillers and catalytic supports are halloysite and montmorillonite. The unique layered structure of montmorillonite allows the synthesis of metal-based catalysts supported on the nanoclay by controlling the distance between the layers and creating active sites on the layers for carrying out organic reactions. Montmorillonite-based bifunctional acid-base catalysts are currently used in highly selective catalytic reactions. Halloysite nanotubes (HNT) have been used as support material for platinum, rhodium, ruthenium, and nickel-based catalysts in various applications. In the present chapter, we discuss about the nanocomposites formed of halloysite and montmorillonite-based nanofillers. We further focus on the use of the clay minerals as catalyst support with inorganic nanoparticles as filler material. We elucidate on the enhancement of catalytic and composite properties by the use of nanoclay.