Previous research has studied service quality because the delivery of higher service quality isthe strategy that may posit service providers more effectively in the competitive market place. To manage service quality it is essential to use a proper measurement model for service qualityeven though service quality is difficult to define and measure. The SERVQUAL, which is themost popular measure of service quality, defines service quality as the perceptions-expectationsgap conceptualization. In other words, this measure is conceptualized as a gap between whatthe customer expect from a class of service providers and their evaluations on performance of aparticular service provider. Parasuraman et al. (1985) identifies the ten components of servicequality (reliability, responsiveness, competence, access, courtesy, communication; credibility,security; understanding/knowing the customer, and tangibles) and Parasuraman et al. (1988)again classify the ten components into five dimensions (reliability, assurance, tangibles, empathy,and responsiveness). However, the SERVQUAL’s five dimensions may not be permanent anduniversal; the number of dimensions is contextualized; there is a high degree of inter-correlationbetween the five dimensions [see Buttle (1996) and Cronin & Taylor (1992) for more details]. Cronin and Talyor (1992) and Buttle (1996) point out that consumers’ evaluations on servicequality may be affected by consumers’ involvement. However, it is not easy to find a studydevoted to systematically investigate the role of consumers’ involvement on consumers’ evaluationsof service quality. How does consumers’ involvement Influence consumers’ evaluation of servicequality? This paper designs to answer the question. It briefly reviews previous studies on servicequality. Next it investigates the role of involvement in consumers’ evaluations on service quality based on Boulding et al.’s (1999) bayesian data integration and updating processes frameworkfor consumers’ assessing service quality. Then, it proposes three hypotheses on consumers’evaluations on service quality. To validate the hypotheses, this paper designs and conductsempirical studies for four different service categories. This paper ends with the conclusions,limitations, and extensions. Data was gathered from personal interviews conducted in a city in South Korea. A total of1,140 usable questionnaires (all questions answered) were gathered by trained interviewersduring a three-week period in the summer of 2014. Responses were gathered on service qualityoffered in each of four industries: four firms for Bakery, four firms for Family Restaurant, eightfirms for Fast Food (four for Hamburger and four for Pizza), and four firms for Movie Theater. The sample size for each industry was 306 for Bakery, 273 for Family Restaurant, 584 for FastFood, and 247 for Movie Theater. The firms and industries were chosen because the serviceindustries are familiar to the respondents. The firms chosen with each industry were a half withthe largest sales and the other half with the smallest sales. Respondents were screened to determinewhether they had used one of the service providers included in the study within the last 60days. The measures needed for the study were expectations (‘Should Expectations’) and perceptionsof performance to construct the SERVQUAL measures of service quality. The 22 expectationand the 22 performance items were taken directly from the SERVQUAL (Parasuraman et al. 1988). The measures of service quality were based on responses to 7-point semantic differentialquestions. In addition, self-report measures of overall service quality and consumer satisfactionwere constructed with 7-point semantic differential questions. T-tests and regression analyses were used to test the three hypotheses on service qualitywhich were developed based on the proposed bayesian data integration and updating framework. The T-tests showed that the respondents of higher involvement group expected and perceivedthe service qualities of five service quality dimensions highly than those of lower involvementgroup for the four service categories. In addition, the regression analyses revealed that predictionsof the five dimensions of service quality on overall service quality (or customer satisfaction) inthe higher involvement group higher than in the lower involvement group for the four servicecategories. The results support that consumers assess service quality based on a bayesian dataintegration and updating processes, and imply that the bayesian updating processes are affectedby consumer involvement.