The use of nanotechnology in the finishing of technical textiles has resulted in imparting new and more complex functions on textile substrates as well as improvements in existing functions such as durability without losing the fabric’s feel and texture, with the minimum use of chemicals. The evolution, advancement, theory and technology of application of some of the commercially successful nano-finishes that impart hydrophobic, super-hydrophobic, self-cleaning and antimicrobial properties are discussed in this chapter.