Nanofillers are filler materials that have a dimension in the range of 1–100 nm. Owing to their potential physical characteristics, i.e., large surface areas, low structural imperfections, and high surface energy, nanofillers are known as popular fillers as compared to microfillers. Nowadays, they are considered a ubiquitous choice for applications in various fields, from the biomedical industry to household goods, including the catalysis industry. Nanofiller-based materials are considered potential candidates in the catalysis industry as they are easy to synthesize with the desired structure, composition, size, and morphology. Organic, inorganic, carbon, and clay-based nanofillers are important fillers that have a great role in the catalysis industry. Nanofiller-based catalysts are emerging as an alternative to conventional catalysts used in various kinds of catalysis applications, such as catalysis in energy production, photocatalysis, and electrocatalysis. The effect of nanofiller in the catalysis industry has been found to accelerate the various reactions in a cost-effective and selective way, along with a high-quality final product. In this chapter, various ways to synthesize nanofiller-based catalysts, their advantages, and their applications in catalysis processes such as chemical catalysis, photocatalysis, electrocatalysis, and environmental catalysis will be discussed.