Abstract A biodegradable composite and nanocomposite made from cassava starch and rice husk fiber were prepared using the solution-casting method. Cellulose was extracted from the rice husk via chemical treatment and cellulose nanocrystals (CNCs) were isolated via acid hydrolysis. The microstructures, crystalline structures, and thermal, mechanical, and water uptake properties of the biocomposites and nanocomposites were characterized. It was found that the storage modulus, tensile properties, thermal stability of the starch biocomposite (SB)–CNC increased, whereas the water uptake decreased. From the results, it can be concluded that CNC is highly compatible with starch and can reinforce the starch phase to produce green nanocomposite films for use as food packaging films and shopping bags.