Mannitol is a polyol or an alditol that is naturally found in many plants and can be produced by several microorganisms. Based on its beneficial physiological effects, mannitol is currently used as a functional sweetener in the food industry. In addition, mannitol has applications in pharmaceutical, chemical and medical industries because of its promising advantages. Mannitol can be produced by extraction, chemical synthesis, or fermentation. Certain mutants have been constructed for different purposes. In this review, we focused on recent advances in the applications and biotechnological production of mannitol.