School-level inefficiencies and mismanagement can have serious repercussions for human resource development and labor market outcomes. This paper investigates the extent and consequences of existing technical inefficiency of schools with respect to their resource- and people-management aspects at a cross-country level across Organisation for Economic Cooperation and Development (OECD) and the Middle East and North Africa (MENA) regions. It employs a non-radial Data Envelopment Analysis (DEA) alongside a second stage Tobit regression model using datasets in the latest Trends in International Mathematics and Science Study (TIMSS) 2019. The analysis covers 5164 schools across 26 countries. In the first stage of DEA analysis, it is evident that technical inefficiencies exist similarly across schools of both OECD and MENA nations, irrespective of the method used for efficiency calculation. While availability of educational resources is a necessary condition for improving learning outcomes, it is surely not sufficient. In the second stage of the Tobit regression, the model confirms that improved utilization of the existing resources through better educational management systems can yield higher cognitive achievement at the school-level. The empirical findings also reveal that discipline maintained within the student body at school is one of the most important and significant factors associated with higher school level input- and output-efficiency across both MENA and OECD regions. Moreover, different aspects of people management, particularly target setting, student as well as teacher motivation, and parental involvement in school management are found to be positively associated with school-level technical efficiency across the two regions, albeit in varying degrees. Overall, educational management policies should shift focus from solely providing higher quantity of resources to improving the technical efficiency of schools through enhanced school-level management, by encouraging disciplinary action, as well as by supporting stakeholder incentives that foster motivation and participation.