Conventional textile wet processing is characterized by a high concentration of chemicals and very high temperatures, which can have considerable negative effects on the environment and energy consumption. Enzymes are one of the paramount interests in textile wet processing towards sustainable development and low energy consumption. Enzymes have been successfully used in many textile processes such as desizing, bio scouring, biopolishing, and bio stoning. Different studies also describe how enzymes could be used for the decolorization of dyes from textile effluents. There is evidence of improved dyeability of different fibers like cellulose and nylon when treated with enzymes before dyeing. In this chapter, the history, definition, functions, and different types of enzymes will be discussed. Enzymes used in different textile processes such as pretreatment, washing, and fishing will be described briefly. This chapter will also give insight into the enzymes used for the decolorization of dyes from the effluent, and for increasing the dyeability of cotton and nylon fibers.