<p>Protein-based biomaterials are growing in popularity for biomedical applications, in part owing to their innate ability to interface with biological systems. These materials, in the form of fibres, nanoparticles and hydrogels, have shown promise as drug delivery vehicles, tissue scaffolds and vaccines. Moreover, the explosion of protein engineering tools and the inception of de novo protein design have transformed our ability to explore new protein structures, enabling the creation of novel materials with diverse properties and furthering their customization for various applications. In this Perspective, we explore the coming of age of protein engineering technologies and their impact on biomaterials. Starting with naturally sourced materials, we highlight common protein building blocks and fabrication methods, as well as recent applications of each. We subsequently explore rationally designed materials and conclude by discussing the potential impacts that de novo design will have on the biomaterials field.</p>