The occurrence of squamous cell carcinoma of the lid is reviewed with emphasis upon the incidence, clinical presentation, pathophysiology and methods of treatment. Squamous cell carcinoma accounts for about 9% of all eyelid malignancies, although it is frequently over-diagnosed by pathologists and confused histologically with other benign entities. This lesion occurs most commonly in elderly, fair-complexioned individuals with a history of chronic sun exposure and skin damage. In the lids, squamous cell carcinoma shows a variety of clinical appearances although it usually presents as a painless, hyperkeratotic lesion that gradually enlarges and eventually ulcerates. There is a tendency for lower lid and lid margin involvement. This potentially lethal neoplasm is capable of aggressive local spread or metastasis to regional lymph nodes. The development of squamous cell carcinoma is thought to progress through phases of intraepithelial squamous dysplasia and intraepidermal squamous cell carcinoma before invasive squamous cell carcinoma occurs. Various treatment modalities have been advocated including surgical extirpation with histologic control, radiation therapy and cryotherapy.