The presence of proteins in food products is highly relevant from a nutritional point of view. Regarding formulated food products, in addition to their nutritional relevance, proteins may also play an essential techno-functional role. Since proteins are complex macromolecules, their molecular and colloidal behaviors are dictated by their chemical nature. Proteins from different sources or subjected to different processes may display different techno-functional behaviors. In this context, characterizing proteins in terms of their techno-functionalities appears as an important strategy to reduce empiricism in their applications by the food industry during product development. This chapter will address different methods for characterizing the techno-functional properties of food proteins, grouping them into (i) solubility and swelling power, (ii) interfacial properties, and (iii) gelation.