This article contributes to current debates in materialist geopolitics and contemporary IR theorising by restating the centrality of social forces for conceptualising geopolitics. It does so by offering a detailed conceptual reading of the corpus of the ‘Eastern Question’, which is composed of a series of political analyses written by Marx and Engels in the period of 1853–6. This archive presents unique analytical and conceptual insights beyond the immediate temporal scope of the issue. I unpack this argument in three movements. The article (i) offers an overview of the debates on materialist geopolitics; (ii) contextualises the historical setting of the ‘Eastern Question’ and critically evaluates the great powers’ commitment to the European status quo; and (iii) constructs an original engagement with a largely overlooked corpus to reveal the ways in which Marx and Engels demonstrated the interwoven relationship between domestic class interests, the state, and the international system. I maintain that revisiting the ‘Eastern Question’ corpus (i) bolsters the existing materialist frameworks by underscoring the role of class as an analytical category; (ii) challenges an important historical pillar of the balance of power argument; and (iii) empirically strengthens the burgeoning scholarship in international historical sociology.