This article argues that in asymmetric international relationships, gratitude functions as a technology of disciplinary power through which material assistance is converted into moral indebtedness. Unlike material conditionality, which constrains what subordinate actors can do, gratitude constrains what they can say, claim, and be within the relationship, delegitimizing resistance by recoding it as emotional deviance. Integrating Maussian gift theory, emotional-regime analysis, and speech-act approaches to emotion, the article theorizes a specific causal sequence: material assistance is framed as a morally valorized gift, which generates a debt of gratitude, which prescribes an emotional performance of acknowledgment and deference, which in turn constrains the subordinate actor’s capacity to contest donor authority. Empirically, the argument is developed through a comparative emotional-discursive analysis of two structurally asymmetric alliances: the Soviet-Cuban relationship during the 1962 Missile Crisis and the U.S.-Ukraine relationship (2022–2025). Across both cases, great powers mobilized gratitude as a reactive disciplinary instrument, deployed to reassert authority at moments when influence risked erosion. The article contributes to the emotional turn in IR theory by demonstrating that hierarchy is mostly sustained through emotional regimes that prescribe what subordinate actors must feel, display, and acknowledge.