This study aims to analyze the effect of service quality on customer satisfaction in forming the loyalty of bus customer Sugeng Rahayu in Yogyakarta. In this study the sample obtained as many as 99 respondents selected by using purposive sampling method with data collection techniques using questionnaires. The analysis tools used are Simple Linear Regression Analysis, Multiple Regression Analysis and Path Analysis using validity test, reliability test, t test and coefficient of determination by using SPSS 25.0 application. Based on the analysis that has been done obtained that: (1) Quality of service have positive and significant influence to customer satisfaction of bus of Sugeng Rahayu. (2) Quality of service have positive and significant influence to customer loyalty of bus of Sugeng Rahayu. (3) Customer satisfaction has a positive and significant impact on customer loyalty of Sugeng Rahayu bus. (4) Customer satisfaction can mediate the influence of service quality on customer loyalty