Yekunoamlak AlemuLijalem Getahun2026-11-102026-11-102026-06-01https://etd.aau.edu.et/handle/123456789/9454School climate serves as a critical psychosocial determinant of student success, yet in the Ethiopian context, institutional focus remains largely limited to physical resource allocation. Understanding the human and organizational factors that cultivate high achievement is vital for addressing the performance divide in urban educational centers. This research investigated how multi-dimensional school climate dimensions directly determine Grade 12 academic achievement levels in the Lideta Sub-City of Addis Ababa. The study used a mixed-methods sequential explanatory design to examine the persistent performance gap between government and private institutions. Data collection involved 175 students and 125 teachers from four specific schools: Kefitegna-23, Ewuket Lefere, New English Private School (NEPS), and Omega. To quantify the relationship between the research variables, school climate was measured using the School Climate Index (SCI) and an adapted student survey. At the same time, academic achievement was analyzed using official Grade 12 National Examination results. Quantitative results demonstrated a significant climate gap across sectors (p < .001). The independent samples t-test revealed that higher outcomes in private schools were strongly associated with principal visibility and teacher respect. In contrast, the lower performance in government schools was linked to facility challenges and minimal parent involvement. The study found that a robust culture of high academic expectations in private institutions directly supported their 39.51% pass rate, whereas bureaucratic burdens and library misuse hindered the government sector. In response to identified safety fears among female students and a pervasive "surrender mentality" regarding exam failure, the researcher recommended that the Sub-city hire professional female psychologists to provide targeted psychosocial support. Policy implications include the allocation of budgets for teacher tutorial incentives to mirror private-sector success. Finally, school leaders must protect academic spaces like libraries for study only and implement digital tools to improve home-school communication.enSchool ClimateAcademic AchievementLideta Sub-cityGovernment and Private SchoolsGrade 12.Thesis