Surface plasmon resonance (SPR) offers exceptional advantages such as label-free, in-situ and real-time measurement ability that facilitates the study of molecular or chemical binding events. Besides, SPR lacks in the detection of various binding events, particularly involving low molecular weight molecules. This drawback ultimately resulted in the development of several sensitivity enhancement methodologies and their application in the various area. Among graphene materials, graphene-based nanocomposites stands out owing to its significant properties such as strong adsorption of molecules, signal amplification by optical, high carrier mobility, electronic bridging, ease of fabrication and therefore, have established as an important sensitivity enhancement substrate for SPR. Also, graphene-based nanocomposites could amplify the signal generated by plasmon material and increase the sensitivity of molecular detection up to femto to atto molar level. This review focuses on the current important developments made in the potential research avenue of SPR and fiber optics based SPR for chemical and biological sensing. Latest trends and challenges in engineering and applications of graphene-based nanocomposites enhanced sensors for detecting minute and low concentration biological and chemical analytes are reviewed comprehensively. This review may aid in futuristic designing approaches and application of grapheneous sensor platforms for sensitive plasmonic nano-sensors. Graphene nanocomposites based sensitivity enhancement methodologies for chemical and biological sensing. (a) oxidant and reducing gases sensing by oxygen atom of GO with surface reaction mechanism. (b) Protein binding interaction directly on GNC (grapheneous nanocomposites) surface. (c) Antigen: antibody (Ag:Ab) reaction of directly immobilized Ag:Ab on to GNC. (d) pi-pi stacking for planer structure. (e) Hydrogen or electrostatics attraction based binding (f) direct sensing of molecules (shown here for ammonia gas). Display omitted •Presents graphene nanocomposite based SPR sensors.•Recent progresses in SPR signal enhancement by graphene nanocomposites has been overviewed.•Graphene nanocomposites based sensitivity enhancement methodologies for chemical and biological sensing is reviewed.•In this review, we discussed future trends and perspectives to lay down the future SPR based plasmonic nano-sensors.