The purpose of this study was to investigate how leadership and organizational culture influence teachers’ organizational citizenship behavior (OCB) in the public universities in the Amhara Regional State, with learning organization practices serving as a mediating variable. A quantitative research approach was employed, using a descriptive and correlational cross-sectional survey design. Data were collected from 647 teachers and analyzed through one-sample t-tests, correlation analysis, and structural equation modeling using AMOS software. Results showed that teachers generally demonstrated high levels of OCB, with courtesy emerging as the strongest dimension. Among leadership styles, only transformational leadership significantly and positively predicted OCB, while transformational, transactional, and laissez-faire leadership together explained 11% of its variance. Within organizational culture, mission had a stronger positive effect than the negative impact of adaptability, and together the traits explained 22% of OCB variance, indicating a large effect. Learning organization dimensions explained 34% of the variance, with personal mastery identified as the strongest predictor. Transformational leadership demonstrated the most positive but largely indirect influence on OCB, transactional leadership contributed modestly, and laissez-faire leadership negatively affected OCB. Both leadership and organizational culture affected OCB primarily through the mediating role of learning organization, with systemic team learning offering a contextual adaptation of Senge’s framework. Demographic analysis revealed significant differences in OCB across university generations, particularly between first, second, and third-generation universities, Overall, the findings highlight that fostering teachers’ discretionary behaviors requires an integrated approach aligning leadership, organizational culture, and institutional learning systems. The study advances theory by underscoring learning organization as the central mechanism linking leadership and culture to OCB, while recommending that universities strengthen learning cultures and reform bureaucratic structures. Future research should employ longitudinal and mixed-methods designs to establish causality and enhance generalizability across diverse higher education contexts.