Polypeptides are functional biomolecules that play a key role in life science, where they can act as hormones and signaling molecules. They can self-assemble into a variety of nanostructures, including two dimensional (2D) lamellae, one dimensional (1D) nanofibrils and nanotubes, and zero dimensional (0D) nanospheres. The driving force behind these advanced nanomaterials involves weak non-covalent interactions that include hydrogen bonding, and hydrophobic and electrostatic interactions. Here we discuss each of the interactions in relation to self-assembly and provide examples of some novel applications in engineering materials, tissue engineering and nanoelectronics. The overall aim is to provide a comprehensive, yet easily accessible review of the known nanomaterials produced by self-assembling polypeptides, which may lead to the construction of more advanced polypeptide nanostructures for future applications.