In service industry that is growing rapidly, customer satisfaction is the main key for every company to survive from very tight competition. Service quality has an important role because it is a component that can meet customer satisfaction. One of the challenges of the Ondo Grill Batak restaurant as a long-standing restaurant is to maintain and improve the quality of their services along with the many innovative newcomer restaurants. Service quality in this study using the dimension that was triggered by Parasuraman, Zeithaml, and Berry namely reliability, responsiveness, assurance, empathy and tangibility (Tjiptono and Chandra, 2017) and customer satisfaction by using indicators triggered by Hawkins and Looney in Nuridin (2018), namely conformity of expectation, interest in visiting again and the willingness to recommend.This study uses quantitative research design and convenience sampling method. Data were collected from 88 of Ondo Grill Batak restaurant Medan customers. There are central tendency and 8 data analysis test that will be used in this research, which are validity test, reliability test, normality test, correlation coefficient test, determination test, regression line test, linearity test and hypothesis testing.The result of this study shows that service quality has an influence towards customer satisfaction at Ondo Grill Batak restaurant Medan. This is proven by the correlation test that is equal to 0.656 which means both variables have a relatively strong correlation. Therefore, the better service provided by Ondo Grill Batak restaurant Medan to the customers, the higher level of customer satisfaction.Meanwhile, two aspects that need to be improved are responsiveness and empathy.