This entry approaches its topic through the perspective of the role of language and ideology in politics and the exercise of state power. It begins by introducing the analyses of Marx (and Engels) on language and its evolution, then considers the relation between their approach to language and ideology in the French Enlightenment sense of the science of ideas (a key influence in Marx’s work), and finally considers the relation between language, ideology, and politics. It notes that Marx rarely referred to ideology as such, usually qualifying the noun (e.g., German Ideology, petty bourgeois ideology) or employing ideology as an adjective to supplement a noun (e.g., ), and then explores the successive ways in which Marx explores ideology, distinguishes it from science, and engages in Ideologiekritik. Referencing, inter alia, the Eighteenth Brumaire of Louis Bonaparte, it also indicates that Marx called for a new political ‘language’ (‘a poetry of the future’) as a precondition for a radical transformation. After some brief comments on the concept of ideology in the Second International and Marxism-Leninism, the analysis turns to the work of Antonio Gramsci, noting the significance of his university studies in philology (specifically historical and spatial linguistics) and then focusing on his Prison Notebooks. It introduces four key concepts and their use in Gramsci’s notebooks: ideology, intellectuals, hegemony, and the state as hegemony armoured by coercion. It also considers folklore, popular culture, and the national-popular. This enables a discussion of the role of struggles for hegemony in the politics of democratic polities or, at least, societies in which mass politics is important. Following another brief interlude on alternative approaches to language and politics in inter-war Western Marxism, the analysis turns to the work of the so-called structural Marxist, Louis Althusser. The key texts here concern those that address ideology, ideological state apparatuses, interpellation, and the expanded reproduction of capitalist social relations. Here I analyse the early analysis of ideological state apparatuses (which involves a critique of Gramsci’s historicism) and a later rapprochement with Gramsci’s work on hegemony. The chapter concludes with a comparison of the work of Marx, Gramsci, and Althusser on language, ideology, and politics, emphasizing continuities as well as discontinuities, and assessing their contemporary relevance.