The purpose of this research is to investigate the casual relationship among service qualityrndimen ion and overall ervice quality and overall customer atisfaction, and identify servicernquality gap a experienced by institutional customers. Modified SERVQUAL model was used tornmeasure the perceptions and expectations of broadband internet service customers of ETC. Therntudy employed survey approach using structured questionnaire for the purpose of datarncollection, and a ample of 141 respondents was drawn using convenience sampling techniquernand 129 usable questionnaire were collected for final analysis. The eight modified dimensionsrnof 'ERVQUAL, such as quality of network, service price, reliability, responsiveness, empathy,rna surance, tangibles, and after sale service (a total of 35 statements) was used to measurernCll tomers' perceptions and expectations of the quality of broadband internet services u ing 7rnpOint Likert type cale with 1 being very low and 7 being very high.rnThe cale reliability (Alpha) of the modified SERVQUAL model was found to be 0.953. Withrnregard to the service quality gaps, the highest gap was found in quality of network (-3.21)rnfollowed by after sale service (-2.79). The other fundamental findings of the study were thernregre ion model for overall customer satisfaction and overall service quality. Three regreSSionrnmodel were found for overall customer satisfaction. In the first model, quality of networkrnexplains 36.90% the variation in overall customer satisfaction. In the second model, quality ofrnnetwork and after sale service as the only predictors, explains 42.80% of the variation in overallrncustomer satisfaction and the third model explains 44.40% of the variation led by the predictors 'rnquality of network, after sale service & empathy. Likewise, two regression models were found forrnoverall service quality with quality of network as the only Significance predictor for the firstrnmodel explains 29.50% of the variation in overall service quality. For the second model, qualityrnof network and after sale service together explains 35.90% of the variation. Since the servicernquality gaps for all the dimensions were negative and high, ETC has to perform a lot to narrowrnthese gaps by managing customer expectations. In addition, quality of network & after salernservice dimension were found to be the determinant of both overall service quality and customerrnsati ifaction; ETC should focu on the items of these dimension.rnKeywords - SERVQUAL, customer sati ifaction, service quality, perceptions and expectations,rnquality gaps, broadband internet service, Ethiopian Telecommunications Corporation.rnPaper type- Thesis