Although donor-driven Public Sector Reforms (PSRs) are believed to improve the performance of the public sector, their implementation in African countries such as Zambia has resulted in administrative chaos. The purpose of this article is to re-theorise donor-driven PSRs in Zambia using the concept of Rational Administrative Chaos (RAC). The research relied on secondary data involving 20 documents. The findings reveal that rather than enhancing efficiency, donor-driven PSRs lead to RAC. This is done by implementing New Public Management reforms to weaken the government and allow donors to make profit through public debt. Collaborative Public Management reforms are then implemented to manipulate the government in service delivery. In turn, public debt is used to pay for undelivered or poorly delivered services. Private companies then accumulate capital. In line with rational choice theory, administrative chaos is not an accidental failure of the reforms but a rational choice by state actors making a trade-off between external donor conditionalities and domestic political survival. The main contribution of this article has been to shed light on how donor-driven PSRs lead to institutional instability and failure to serve the public interest in Africa.