Oral cancer is classified based on the type of cell where the cancer (carcinoma) originates. Squamous cell carcinoma is the most prevalent form, accounting for approximately 90% of all oral cancer cases.

Other, less common types of oral cancer include:
* Adenocarcinoma: Cancers that develop within the salivary glands.
* Sarcoma: Cancers arising from abnormalities in bone, cartilage, muscle, or other connective tissues.
* Oral malignant melanoma: Cancers originating in cells that produce skin pigment (melanocytes), often appearing as very dark, speckled, and frequently bleeding growths.
* Lymphoma: Cancers typically developing from cells found in the lymph nodes, though they can also manifest in the oral cavity.

It is important to note that oral cancer is considered a type of 'head and neck cancer'. Other cancers classified under this umbrella include:
* Laryngeal cancer
* Nasopharyngeal cancer (affecting the area behind the nose, forming the upper part of the pharynx)
* Oropharyngeal cancer
* Hypopharyngeal cancer
* Thyroid gland cancer
* Nose and sinus tumors
* Esophageal cancer