Purpose: This study investigates the partial and simultaneous effects of work commitment, work discipline, and competence on teacher performance at Sekolah Guang Ming Medan, a private educational institution in North Sumatra, Indonesia, where suboptimal teacher performance has been observed in commitment consistency, disciplinary adherence, and professional competency alignment.
Methodology: A quantitative survey design was employed. The study population comprised all 53 permanent teachers at the school, and a census sampling technique enrolled all 53 individuals as respondents. Data were collected through structured Likert-scale questionnaires. Instrument validity was assessed using Pearson correlation and reliability via Cronbach's alpha. Classical assumption tests and multiple linear regression analyses were conducted using IBM SPSS Statistics version 20.0.
Results: All instruments were valid and highly reliable. Work commitment (t = 2.285, p = .003), work discipline (t = 1.850, p = .000), and competence (t = 1.760, p = .004) each exerted positive and significant partial effects on teacher performance. The simultaneous F-test confirmed joint significance (F = 175.34, p = .000), with the three predictors jointly explaining 81.2% of the variance in teacher performance (Adjusted R² = 0.812).
Conclusions: Competence produced the largest marginal performance gain (B = 0.213), followed by work discipline (B = 0.161) and work commitment (B = 0.048).
Limitations: The single-school census design restricts generalizability, and the cross-sectional approach limits causal inference.
Contributions: This study provides the first integrated threepredictor quantitative analysis of teacher performance determinants at Sekolah Guang Ming Medan, offering evidencebased guidance for school human resource management.