The dispute settlement system of the World Trade Organization (wto) prides itself on its high degree of judicial independence and the impartiality of its adjudicators. Yet compared to other international tribunals, wto member states exert considerable political control over wto adjudicators. Contestation over the appointment of those adjudicators also reflects governments’ awareness that nationality may matter for outcomes.The authors ask whether that is the case. An empirical analysis of twenty-five years of wto Appellate Body (ab) activity offers a nuanced answer. Exploiting the random allocation of adjudicators to ab divisions, the authors find no evidence of systematic national bias across the board.Yet evidence does exist of bias on the part of ab division chairs, suggesting that when adjudicators are singled out, they become more prone to political pressure. A similar effect pertains to individual dissenting opinions.The presence of a conational from a litigant country on an ab division is associated with significantly increased odds of dissent. Judicial independence at the wto has long been taken for granted.These findings suggest that such trust is largely warranted, but even small tweaks in institutional design increase political pressure on adjudicators in ways that threaten impartiality, which holds significant implications for wto reforms going forward.