The aim of this thesis is to gather more knowledge about the impact of service quality on customer satisfaction in “One bank Ltd” in Bangladesh. Nowadays the market of the serviceproviding firm is highly competitive and the expectation of the customer is increasing. The firms are required to focus more on the service they provide to satisfy the customer in order to achievethe goal of a organization. The main purpose of this thesis is to identify the influencing factor ofservice quality that leads to the customer satisfaction. In this thesis the research approach are used are combination of both the inductive and deductive approach. The study is quantitative in nature. Structured questionnaire are used in order to collect the data. The theoretical framework used in this thesis is SERVIQUAL model developed by Parasuraman et al. (1998). The empirical findings of this thesis indicate that the customer of the “One bank ltd” is satisfied with th eservice they provided. From the empirical findings it shows that the better service providing firm can get advantage of market share. The service quality model can help the banking sector of Bangladesh to build a strong market and service provider can get advantages from providing better service.