Nut shells are an abundant and underutilized waste of the agro-food sector. Its valorization in the production of nanobiocomposites is a possibility to exploit its renewable content producing advanced bio-based materials with tailored thermomechanical and functional features for high-performance applications. In the present chapter, the most important nut shells were explored in connection with global and local food production. Then the production of biocomposites from the different nut shell micrometric powders was explored considering their importance in applications in furniture, automotive, packaging, and personal care/biomedical applications. This analysis suggested that the use of bio-based and compostable matrices is currently more explored in this latter field. Finally, the use of nut shell in nanobiocomposites was surveyed considering the possibility to exploit nanoparticles coming from nut shell or the possibility to exploit compounds/components obtained by extraction of molecules or conversion to cellulose or lignin of the nut shell waste. This last part revealed, in good agreement with the previous one, that nut shell agro-waste is currently an important source for new highly-technological biorefinery chains in agreement with circular economy and a more sustainable way of producing consumer goods.