This study is to gain better understanding of the impact of service quality on customer satisfaction of a Telecommunication Company in Bangladesh. In today's highly competitive market environment and with growing customer expectations, companies are trying to maintain effective customer service that helps to build customer's relationship so that customers are satisfied. The purpose of this study is to identify the relationship between service quality and customer satisfaction. The findings of this study show that service quality in the company is more than sufficient implying customers are overly satisfied and subscribers are loyal and satisfied with the services offered to them and are ready to recommend others. The results of the study also indicated that service quality and customer satisfaction are significantly and positively related to each other. However, understanding and studying of the relationship among all the variables of service quality can helps mobile service providers to identify the suitable course of action that need to be taken to achieve trustworthiness of customers by providing better services so that a firm can achieve economic goals like market share etc.