The keratinized oral gingival epithelium provides effective protection against both mechanical trauma and bacterial invasion. The horny cell layer acts like a film of plastic wrap, allowing the body to retain moisture and protecting it from invasion by foreign substances and comprises various substances such as keratins, produced by the epidermal keratinocytes and lipids. The epidermal keratinocytes divide in the basal layer, produce keratins and differentiate, and migrate to the upper layers as they mature by a process called keratinization. The present review discusses the structure of keratin, the process of keratinization and their distribution in gingival epithelium.