<p>Nanoparticle applications have revolutionized tribological aspects and provided innovative answers to age-old questions of friction, wear, and lubrication. With their unique physico-chemical properties in terms of their high surfaces, tunable sizes, and shape, nanoparticles can be used to achieve much better lubrication with lower friction and wear resistance. Nanoparticles are additives to lubricants, fillers for composite coatings, and agents for surface modification, providing much better tribological performance than conventional materials. Advancements in the synthesis and functionalization of nanoparticles have expanded their applicability beyond automotive and aerospace engineering to many areas of manufacturing. Thus, this review makes comprehensive coverage of nanoparticles in tribology, including action mechanisms with a focus on lubrication enhancement, surface modification, reduction of friction, and improvement of wear resistance. The review touches on current problematic issues, such as environmental and cost-effectiveness, while exploring research and development opportunities in this rapidly emerging domain.</p> Graphical Abstract <p></p>