Functionalizations of poly(vinyl alcohol) congruent with the desired applications are discussed inthis article. The chemical modifications of poly(vinyl alcohol) with different molecular weights and hydrolysis degrees via conventional chemistries, namely esterification, carbamation, and etherification, and via the modern ones such as click chemistry, led to finished materials with a wide range of applications and uses: membrane fuel cells, biologicals and biomedicals, adsorption of heavy metals and other contaminants, molecular sensing or chemosensor for detection of some useful molecules or toxic ones, separation of mixtures, and catalysis in organic and inorganic syntheses. Different forms of the duly modified poly(vinyl alcohol)s were used in such applications, including hydrogels, films, membranes, and nanoparticles. The incorporated modifying agents onto poly(vinyl alcohol) matrixes brought some changes that were in tune with the projected applications. These modifying agents were not confined to molecular compounds but also to macromolecular ones which are graphene, hyaluronic acid, β-cylcodextrin, polystyrene, poly(4-vinylpyridine), and poly(L-lactic acid).