An enormous increase in the use of enzymes in a wide range of industrial biological conversion technologies has been made possible by the explosion of green biotechnology. Industrial enzymes' huge biocatalytic potential gives them an advantage over chemical technology in terms of security, reusability, and greater process regulation. One such enzyme with enormous potential for converting hydrolyzable tannins into gallic acid is tannase. Tannins mostly accumulate in plant components including leaves, fruits, roots as well as bark. Additionally, harmful tannery effluents from a variety of tanneries contain high concentrations of tannins in the chemical form of tannic acid. Tannase is primarily used to degrade the tannins that mostly exist in harmful tannery effluents, offering a comparatively much more affordable method for their biodegradation. This review discusses the mechanism of action of tannases, with an emphasis on substrates and production, biochemical characterization, and its applications.