It is generally accepted that, to move the governmental sector toward better performance, governmental agencies need to adopt high-performance management techniques. One such technique is the HPO (high-performance organization) Framework, which has been applied successfully in many countries. However, most of these applications were in developed countries and in the private sector, which raises the question of whether the framework would work equally well in an African governmental setting. Specifically, this study posits, and proposes to answer, the following three research questions: (a) Can the HPO Framework be used to evaluate the strengths and weaknesses of Zambian governmental institutions and yield tangible recommendations to achieve sustainable high performance? (b) If so, can the performance of these institutions subsequently be shown to improve over time? (c) What is the role of the institutions' managers in a successful implementation of the framework? To explore these considerations, the HPO Framework was applied at three Zambian governmental institutions. In a longitudinal research set-up, the application and accompanying organizational results were tracked. The study results showed that the HPO Framework is indeed applicable in the Zambian governmental sector and can significantly contribute to it becoming high-performing. However, the study's results also made clear that full commitment from management has to be ensured before embarking on an HPO transition. This research is the first of its kind: a longitudinal study of the workings and effects of an HPO framework, in the context of a developing country's governmental sector.