Importance: Lichen sclerosus (LS) is an uncommon chronic inflammatory disease that most commonly affects anogenital skin of postmenopausal women. It typically manifests as atrophic white plaques, which may be accompanied by purpura or fissuring. Rarely, LS has been observed to affect mucosal tissues in the mouth and the penile urethra. It is generally taught that LS does not affect the vagina, unlike lichen planus. To our knowledge, only one case report of LS with vaginal involvement exists in the literature., Observations: Two cases of severe vulvar LS with vaginal involvement are reported. Both cases exhibited characteristic features of LS on vaginal biopsy, and both patients were followed up clinically without further treatment of the vagina., Conclusions and Relevance: Vaginal LS may be more common than previously thought and may be underdiagnosed. Patients with more severe disease or with significant vaginal atrophy may be more likely to have involvement of the vagina. In addition, patients with pelvic organ laxity may be at increased risk if their vaginal walls are chronically exposed because of prolapse. Physicians managing patients with vulvar LS should be aware of the possibility of vaginal involvement so that vaginal lesions may be diagnosed and followed up appropriately.