Wheat kernel hardness is a major quality characteristic used in classifying wheat cultivars. Differences in endosperm texture among Triticum aestivum L. or between T. aestivum and T. turgidum L. ssp. durum cultivars profoundly affect their milling behavior, the properties of the obtained flour or semolina particles, as well as the quality of products made thereof. It is now widely accepted that the presence, sequence polymorphism, or absence of the basic and cysteine-rich puroindolines a and b are responsible for differences in endosperm texture. These proteins show features in vitro, including foaming and lipid-binding properties, which provide them with a potential impact in the production of wheat-based food products, where they may improve gas cell stabilization or modulate interactions between starch, proteins, and/or lipids. We here summarize the impact of wheat hardness on milling properties and bread, cookie, cake, and pasta quality and discuss the role of puroindolines therein.