Background Oral lichen planus (OLP) lesions have an overall malignant transformation rate of 1.37%. In patients with chronic disease, the diagnosis of malignancy relies on histopathological examination guided by clinical suspicion. Narrow-band imaging (NBI) is a promising endoscopic technique which, using a filtered light with specific wavelengths, can highlight microvascular abnormalities associated with subclinical neoplastic changes of the upper aerodigestive tract epithelium. Objectives This study aimed to analyse the value of NBI in selecting patients for biopsy before the emergence of clinical changes, allowing early detection of oral malignancies arising from OLP. Materials and methods A prospective study was conducted, enrolling 32 consecutive patients with a histological diagnosis of OLP with no previous diagnosis of oral cancer or other oral inflammatory diseases. Patients with suspicious NBI lesions underwent biopsies, while other patients were included in the follow-up. Results Two patients were judged positive at NBI evaluation and squamous cell carcinoma was diagnosed after histological examination. None of the other patients developed clinical features of malignancies during follow-up. Conclusion NBI evaluation may increase the accuracy of detection of subclinical neoplastic transformation in OLP lesions and further encourage clinicians to perform biopsies in selected cases.