Based on an economic model of consumer demand, a multinomial logit model is estimated to predict the probability of a consumer falling into one of four categories of complaint action: no action, private, public, or both private and public complaints. Automobile repair and medical services are used as examples of more and less competitive industries. There are differences across industries with regard to variables that explain variation in complaints. Once variables representing the cost/benefit, learning, restraints, and personality models are accounted for, most of the variation in complaint behavior for both industries is explained by the learning and restraints models. Characteristics of individuals are important in explaining complaint behavior for both auto repair and medical services, while supply side characteristics are important in explaining variation in complaint behavior for auto repair services.