Between October 2000 and January 2007, 24 horses were presented with suspected squamous cell carcinoma (SCC) of the third eyelid. The hospital’s medical records were analysed retrospectively to gain data about the cases, and telephone follow-up was obtained from the owners and referring veterinary surgeons. The resected third eyelid was submitted for histological examination in 21 cases; in the other three cases the tissue was not submitted at the owners’ request, for economic reasons. SCC was confirmed in 16 of these 21 cases, three cases were diagnosed histologically as lymphoid hyperplasia, one as a mast cell tumour and one as a sebaceous gland adenocarcinoma. Long-term follow up over a median period of 41 months revealed no recurrence of SCC or associated problems; six of the 16 confirmed SCC cases were euthanased for unrelated reasons during the follow-up period.