This study focused on improving the service quality of the restaurant staff in terms of communication, assurance and responsiveness at Deutsches Eck pub and restaurant. The researcher conducted the survey of the restaurant service by using questionnaires with 35 selected customers and conducted the interviews with two managements in the Pre-ODI and Post-ODI phases. Interview data was used as qualitative data. Mean and frequency were used as the quantitative data from the questionnaire. Paired Sample T - Test was used to determine the initial impact of ODI in improving the service quality in terms of communication, assurance and responsiveness. After the implementation of the OD interventions to 14 service staffs, those activities were found to be effective. The customers were more satisfied with their expected service in the restaurant. there was significant difference between the Pre and the Post ODI on communication, assurance and responsiveness. Thus, the continuous development is leading the restaurant service to go beyond customer's expectation.
