Background: This research is motivated by the importance of the implementation of Standard Operating Procedures (SOP) and employee competence in improving the performance of apparatus in public service agencies. The Kutai Kartanegara Regency Library Office as a regional apparatus that provides services to the community requires a standardized work system and competent employees so that the implementation of tasks runs effectively and efficiently. Objective: This study aims to analyze the influence of SOPs on employee performance, the influence of competence on employee performance, the simultaneous influence of SOPs and competencies on employee performance and identify the most dominant variables affecting employee performance. Methods: The data were analyzed using multiple linear regression analysis with SPSS software, encompassing validity tests, reliability tests, classical assumption tests, and hypothesis testing (t-test, F-test, and coefficient of determination) to examine the influence of SOPs and competencies on employee performance. Results: The results of the study showed that SOPs had a significant effect on employee performance with a significance value of 0.016, competence had a significant effect on employee performance with a significance value of 0.000, and simultaneously SOPs and competencies had a significant effect on employee performance with a significance value of 0.000. The most dominant variable was competence, while the contribution of the two variables to employee performance was 56.3%. Conclusion: The implications of this study confirm that improving employee performance needs to be supported by strengthening the implementation of SOPs and sustainable competency development.