In December 1979, the 40th Russian Army crossed the Amu River in support of the pro-communist regime in Afghanistan, but after a decade of war and stabilization efforts, Afghanistan nose-dived into instability. Ultimately, the Soviet Union withdrew, leaving behind a country facing a civil war. In 2001, a U.S.-led coalition of more than 40 countries entered Afghanistan and instated a liberal political regime as a stabilization measure. Yet, Afghanistan is still far from stability and peace. The thesis asks: How do the regime/state stabilization efforts of the Soviet Union and the U.S.-led coalition in Afghanistan compare? Acknowledging that the efforts of the two great powers differ in magnitude and duration, as well as in their ideological impetus, this thesis offers a comparative case study of the regime/state stabilization efforts of both eras. Specifically, it compares the building of security forces, the development of institutions, and the development of the economy and infrastructure. Although prior research has examined particular aspects of the Soviet and U.S.-led stabilization efforts in isolation, few sources offer a comparative analysis from a comprehensive view. This thesis contributes to closing that gap. Furthermore, the answer to the research question has implications not only for the stability of Afghanistan but also the regions of Central and South Asia.