The tight competition in food and beverage industry has affected businesses in maintaining its customers. One of the most fundamental factors to measure customer satisfaction is service quality. As it can ultimately improve satisfaction and minimize service failures. This research is conducted at Grand Liberty Restaurant, Medan and aims to determine and analyze the influence of Service Quality on Customer Satisfaction. Based on the researcher observation at Grand Liberty Restaurant, Medan that has established for more than ten years in food and beverage industry has been entering the maturity phase, where this business is still running though with a minimal profit margin. In this research, the researcher used quantitative method and convenient sampling. The population used in this research are customers of Grand Liberty Restaurant Medan with 52 respondents and used the primary and secondary data to obtain the information needed. The quantitative result of the research, yields this simple linear regression equation: y = 13,737 + 0,418