The eyelid protects the eye from environmental insults and helps maintain corneal moisture. At only 0.6 mm thick, periorbital skin is the thinnest cutaneous surface of the body. Mohs micrographic surgery (MMS) excels here, conserving tissue and preserving function. Given that up to 10% of skin cancers arise on periorbital skin, it is imperative that Mohs surgeons understand the function and anatomy of the eyelid, and the repair options for a range of eyelid defects. Basal cell carcinoma (BCC) is the predominant periorbital malignancy, constituting 90–95% of cases. While BCC rarely metastasizes, it can damage surrounding structures. Dr. Mohs published the largest series using MMS to treat periorbital BCC. Out of 1124 cases of primary BCC and 290 recurrent BCCs, the five-year cure rates were 99.4% and 92.4%, respectively. The second most common periorbital malignancy is squamous cell carcinoma (SCC), accounting for 5–10%. Like BCC, SCC presents more commonly on the lower eyelid but not to the same extent as BCC. The metastatic rates of periorbital SCC have been reported to be as high as 21%. Unfortunately, SCC of the eyelid is much more likely to recur and metastasize when compared with other anatomical locations.