The objective of this research is to explain the factors influencing citizen satisfaction in getting public service in The Investment and One-Stop Service Agency of Tanah Bumbu Regency. In particular, this research seeks to analyze the level of citizen satisfaction and analyze the extent to which Awareness Factor, Rules Factor, Organizational Factor, Income Factor, Skill-Ability Factor, and Service Facility Factor influence Citizen Satisfaction in getting Public Service. This study uses a quantitative and qualitative research approach (mixed methodology) with a sequential mix method, namely a sequential explanatory strategy. Research variables are operationalized into indicators, which are converted into questionnaires that are distributed to service users at The Investment and One-Stop Service Agency of Tanah Bumbu Regency with the type of questionnaire used was a closed and structured questionnaire. The sampling technique is a non-probability sampling technique with incidental sampling. Using Slovin's Formula to calculate the number of samples is 93 service users. The quantitative data was analyzed by the SmartPLS 3.0 program. The findings in this study show that the level of citizen satisfaction in the Investment and One-Stop Service Agency of Tanah Bumbu Regency is included in the category "Satisfied" with the accumulated index value of 3.88. Furthermore, Citizen satisfaction with public service has an R-square value of 0.705 and it can be categorized as a "good" model which can be explained that the variable of Citizen Satisfaction with Public Service is influenced by variables of Awareness Factor, Rules Factor, Organizational Factor, Income Factor, Skill-Ability Factor dan Service Facility Factor for 70,5%. Whereas factors influencing citizen satisfaction in getting public service are Awareness Factor, Rules Factor, Organizational Factor, and Skill-Ability Factor has a positive and significant influence on citizen satisfaction in getting public service with P Values is less than 0.05 and T Statistics is bigger than 1.96. Besides, Income Factor and Service Facility Factor do not have a positive and significant influence on citizen satisfaction in getting public service with P Values is bigger than 0.05 and T Statistics is less than 1.96.