Primary extramedullary plasmacytomas of the eyelid are rare with only five other cases reported in the literature. A 43-year-old Chinese man presented with painless swelling of the left lower eyelid that developed over the past two years. An incisional biopsy and histopathological analysis of the lesion revealed a primary extramedullary plasmacytoma of the eyelid. The tumour was completely excised. There has been no tumour recurrence over the last five years. This tumour should be among those considered when encountering an atypical adnexal lesion. A systemic examination, relevant clinical investigations, as well as life-long monitoring are essential for these patients due to the strong association of extramedullary plasmacytoma with multiple myeloma. When a lesion can be completely resected, surgery provides similar results to radiotherapy.