Understanding protein self-assembly is important formany biological and industrial processes. Proteins can selfassemble into crystals, filaments, gels, and other amorphous aggregates. The final forms include virus capsids and condensed phases associated with diseases such as amyloid fibrils. Although seemingly different, these assemblies all originate from fundamental protein interactions and are driven by similar thermodynamic and kinetic factors. Herewe reviewrecent advances in understanding protein self-assembly through a soft condensed matter perspective with an emphasis on three specific systems: globular proteins, viruses, and amyloid fibrils. We conclude with a discussion of unanswered questions in the field.