The efficacy of tumor necrosis factor alpha (TNF-α) inhibitors in the treatment of Inflammatory Bowel Disease (IBD) is well established. Many cutaneous and mucosal lesions have been described under anti-TNF-α therapy, some of them being considered as paradoxical. In this series we aimed to review the cases of oral lichen planus (OLP) in IBD patients under treatment with anti-TNF-α agents. Histologic findings from oral lesions of IBD patients treated with anti-TNF were revised. Three female patients with IBD developed oral lichen planus (OLP) after starting anti-TNF-α therapy. Other etiologies were excluded. In light of the increasing use of TNF-α inhibitors the occurrence of OLP is a potentially emerging side effect, thus we recommend a careful monitoring for oral manifestations in IBD patients treated with anti-TNF-α agents.