Purpose: This study investigates the impact of competence, motivation, and work culture on employee performance, with self-efficacy serving as the mediating variable. It hypothesizes that competence, motivation, and work culture influence self-efficacy, and in turn, self-efficacy affects performance. Research methodology: The sample in this study were all Medical Support employees at the Tanjungpinang City Regional General Hospital. The number of samples used was 105 respondents. The data obtained was analyzed using data analysis techniques with AMOS 24.0 software rocks. Results: The findings reveal the significance of these relationships: Competence positively affects self-efficacy, as indicated by CR Value (5.045) and Probability (0.000 < 0.05). Similarly, motivation (CR Value 2.802, P-Value 0.002 < 0.05) and work culture (CR Value 4.267, P-Value 0.001 < 0.05) have a positive impact on self-efficacy. Competence (CR Value 3.066, P-Value 0.002 < 0.05) and work culture (CR Value 2.075, P-Value 0.039 < 0.05) significantly influence performance through self-efficacy. However, motivation does not have a direct significant effect on performance (CR Value 1.157, Probability 0.248 > 0.05). Limitations: The research focuses on 105 Medical Support employees at the Tanjungpinang City Regional General Hospital, employing AMOS 24.0 for data analysis. Contribution: This study underscores the importance of competence, motivation, and work culture in enhancing employee performance via the mediating role of self-efficacy.