Nanocrystalline cellulose (NCC) a rigid rod-like nanoscale material, can be produced from cellulosic biomass including wood and non-wood based materials in powder, liquid or gel forril by acid and chemical hydrolysis. Owing to its unique and exceptional renewability, biodegradability, mechanical, physicochemical properties and characteristics of abundance, the incorporation of a small amount of NCC to the materials matrix (polymer, ceramic and/or metal) enhances the mechanical strength of the latter by several orders of magnitudes. Besides, NCC as a material derived from natural sources has no serious environmental concerns, providing further impetus for the development and applications of this green and renewable biomaterial to fabricate lightweight and biodegradable composites. Surface functionalization of NCC remains the main focus of NCC research to tailor its properties for dispersion in hydrophilic and hydrophobic media. It is of uttermost importance to develop tools and protocols for imaging of NCC in a complex matrix and quantify its reinforcement, antimicrobial, stability, hydrophilicity and biodegradability effect. This review highlights NCC biocomposites, preparation, modification, and potential applications. (c) 2016 Elsevier B.V. All rights reserved.