The Open Balkan Initiative is a regional political initiative launched in 2020 by the leaders of three Western Balkan countries: Albania, North Macedonia, and Serbia. The aim of the initiative is to promote cooperation, economic integration, and political stability in the Western Balkan region. This is being conducted apart from the European Union integration process of these participating countries, and along the Berlin Process, which was set up in 2014 as a platform for high-level cooperation between high official representatives of the Western Balkan Six (WB6) and their pee.rs in Berlin Process’s host countries. The Open Balkan Initiative promises to introduce four fundamental freedoms that shall integrate further the markets and the economies, namely the free movement of persons, goods, services, and capital. As such, this regional initiative promises to deliver the benefits of a preferential trade agreement in terms of regional integration of countries and their economies. This paper analyzes the prospect of the Open Balkan Initiative as an instrument for furthering the integration of the participating states and the region in general. This question shall be analyzed through the lenses of the European Union theories of economic integration, with a particular focus on the spill-over effect paradigm. The ultimate aim is to understand, from the legal and scholarly perspective, whether the Open Balkan Initiative is capable of serving as a constitutional instrument for enhancing regional integration in the Western Balkan region.