The category of quality is treated by economics as a notion that is separated from its substance and its impact on the operation of the real economy. These deficiencies can be discerned in several important theories (competition, equilibrium, growth). Quality, and the concurrent with it innovation that aims at the improvement of quality (of goods, services, operation of social systems), should evoke greater interest among those who create economic knowledge. In contemporary economies quality is equally important as cost and prices of goods. Economic importance of processes that shape quality, as well as the influence that quality exerts on market demand, is emphasised throughout the article. The adoption of the extended notion of quality by economic theories should be helpful in the construction of more realistic economic models.