Oral squamous cell carcinoma (OSCC) is the sixth most common cancer with high morbidity and mortality. MicroRNAs (miRNAs) regulate protein-coding gene expression and are dysregulated in carcinogenesis. This study evaluates miRNA-31 levels in plasma from 25 OSCC patients and 25 controls using qRT-PCR. Results show significantly elevated miRNA-31 in OSCC patients, particularly in moderately differentiated grade 4 cases. The findings suggest plasma miRNA-31 as a potential adjuvant biomarker for OSCC detection. © 2023 Elsevier B.V., All rights reserved.