What explains the revanchism of (post-)imperial states? This question has renewed salience amid Russia’s expanded war against Ukraine in 2022. In this article, we conceptualise revanchism as a foreign policy preference that involves reclaiming territory once controlled. We also advance a new explanation for revanchism that emphasises elite continuity in those states that experience territorial loss. Elite continuity matters because the ruling political class in (post-)imperial states, which was socialised under the old regime, preserves certain beliefs about world politics and the perceived legitimacy of their territorial claims. We show that elite continuity between the Soviet and post-Soviet political leadership in Moscow helps explain Russia’s revanchism better than those alternative explanations that we derive from the International Relations literature. To substantiate our argument, we compile a novel dataset to operationalise elite continuity across regimes and use discursive evidence and other indicators of elite attitudes towards the desirability of reclaiming lost territory. We also discuss the applicability of our theory to other cases.