The primary purpose of this research is assessing the Role of Service Quality on Customer Satisfaction in Ethio Telecom at South Region: Case Hawassa Cit. To achieve this objective both primarily and secondary data were collected. The questionnaires were distributed to 380 fixed line telephone customers in Hawassa city. As a way of trying to measure service quality, researcher was developed a methodology known as SERVQUAL a perceived service quality questionnaire survey methodology. SERVQUAL examines five dimensions of service quality: Reliability, Responsiveness, Assurance, Empathy, and Tangibility. The collected data were analyzed and interpreted by Statistical Package for the Social Sciences in version 20. From the results obtained, the consumers perceive service quality as poor in all dimensions, indicating their expectations was higher than their perceptions for fixed line telephone service at ethio telecom. In this regard, consumers were not satisfied with any dimension of service quality. All dimensions were showing a negative gap score. Ethio telecom need to make improvements in all dimensions in order to close gap and that could lead to increased customer satisfaction.