An olfactory receptor mimetic peptide-modified graphene field-effect transistor (gFET) is a promising solution to overcome the principal challenge of low specificity graphene-based sensors for volatile organic compound (VOC) sensing. Herein, peptides mimicking a fruit fly olfactory receptor, OR19a, were designed by a high-throughput analysis method that combines a peptide array and gas chromatography for the sensitive and selective gFET detection of the signature citrus VOC, limonene. The peptide probe was bifunctionalized via linkage of a graphenebinding peptide to facilitate one-step self-assembly on the sensor surface. The limonene-specific peptide probe successfully achieved highly sensitive and selective detection of limonene by gFET, with a detection range of 8−1000 pM, while achieving facile sensor functionalization. Taken together, our target-specific peptide selection and functionalization strategy of a gFET sensor demonstrates advancement of a precise VOC detection system.