["The World Economy, EarlyView. ", "\nABSTRACT\nThis paper examines the unintended consequences of the 2018–2019 US‐China trade war for Vietnam, a key bystander economy, using quarterly HS 8‐digit US import data from 2017Q1 to 2020Q4. While the average treatment effect on Vietnam's exports to the US is small and statistically insignificant, substantial heterogeneity arises from pre‐war revealed comparative advantages (RCAs). Vietnam experienced markedly stronger export growth in sectors where China held high pre‐war RCA, consistent with trade diversion and substitution effects. These gains were nonlinear and most pronounced in sectors where Vietnam initially had low comparative advantage, reflecting the exploitation of previously untapped export opportunities. Consequently, Vietnam captured meaningful trade‐diversion benefits primarily outside its pre‐existing areas of comparative strength. In addition, we provide consistent evidence that the relocation of MNCs is strongly associated with the observed export surge. By quantifying these spillovers, our study contributes to the literature on global value chain dynamics and trade protectionism.\n"]