Microfiber or microfibre refers to synthetic fibers (fiber) that measure less than one denier. The most common types of microfibers are made from polyesters, polyamides (e.g., nylon, kevlar, nomex, trogamide), and or a conjugation of polyester and polyamide and of polypropylene prolen.

Microfiber is used to make non-woven, woven and knitted textiles. The shape, size and combinations of synthetic fibers are selected for specific characteristics, including: softness, durability, absorption, wicking abilities, water repellency, electrodynamics, and filtering capabilities.

Microfiber is commonly used for apparel, upholstery, industrial filters and cleaning products.

Microfiber is a fiber with less than 1 Decitex per filament (Source: Textile Terms and Definitions, 11th Edition, published The Textile Institute). Decitex is a measure of linear density and is commonly used to describe the size of a fiber or filament. Ten thousand meters of a 1-decitex fiber weighs one gram. Some commercial producers may use a value of less than 1.3 Decitex to define microfibers. Fibers are combined to create yarns which are knitted or woven in a variety of constructions. While many microfibers are made of polyester, they can also be composed of polyamide or other polymers polypropylene.