Abstract.Ultrastructural studies have been carried out on epithelium taken from seven cases of non‐erosive oral lichen planus. Structural abnormalities observed have been consistent with light microscopic findings but no cellular changes specific to lichen planus have been noted. In particular the intranuclear structures seen have been similar to those described in a number of other epithelial disorders. Discontinuities of the basement membrane have been observed, without thickening or duplication of the lamina densa. No evidence of a viral etiology for the condition has been detecte