The present study reports an alternative method of functionalizing the optical fiber Surface Plasmon Resonance (SPR) sensing probe with antibodies for label-free detection of bovine serum albumin (BSA) protein. In this novel approach, the gold coated fiber was first modified with Molybdenum disulfide (MoS2) nanosheets followed by its bio-functionalization with Anti-BSA antibodies. The developed technique not only allowed the amplification of the SPR signals by synergic effects of MoS2 and gold metallic thin film but also enabled a direct and chemical-free attachment of representative antibodies through hydrophobic interactions. The sensitivity of the MoS2 modified sensing probe with detection limit of 0.29 µg/mL was improved as compared to the fiber optic SPR biosensor without MoS2 overlayer (Detection limit for BSA was 0.45 μg/mL). The developed biosensor has good specificity, and environmental stability. Accordingly, the proposed design of the MoS2 based SPR optical biosensor can offer the development of a simplified optical device for the monitoring of various biomedical and environmental parameters.