Initially introduced as a response to the recurrent problem of military coups d'etat, the rejection of unconstitutional changes of government has evolved to become the lynchpin of the African Union's policy on constitutionalism and democratic governance in Africa. However, the prevailing political realities in many African countries, including the (re-)introduction of anti-democratic policies and dubious constitutional manoeuvres by incumbent governments, as well as recent events associated with the so-called ‘Arab Spring’ have highlighted the limitations of the African Union's existing strategy both in theory and practice. Based on a critical analysis of the African Union's regime on unconstitutional changes of government, its normative design and practical application, this article argues that—and explains why—the organisation has so far generally overpromised, but underdelivered, on the stated goal of collectively safeguarding constitutional democracy in its member states. While recognising its achievements in the progressive development and consolidation of a regional norm outlawing unconstitutional changes of government, the analysis identifies a host of conceptual and practical problems that have hampered the capacity of the African Union to effectively deal with diverse forms of illegitimate disruptions of democratic processes in several African countries. Apart from cases involving popular uprisings, in respect of which the organisation is still in search for a coherent policy framework, there is also a lack of conceptual clarity as to which cases of democratic backsliding can be brought under the rubric of unconstitutional changes of government, as well as a general reluctance on the part of the African Union to apply its policy against incumbent governments entangled in unconstitutional preservations of power. The article provides some recommendations aimed at realising the potential of the African Union's normative framework on unconstitutional changes of government as a meaningful tool for the promotion of constitutional democracy in Africa.