The awarding of arbitration costs and attorneys’ fees in international arbitrations is often arbitrary and unpredictable. In one recent investment arbitration where the tribunal deciding a case under the auspices of the international Centre for the Settlement of Investment Disputes (ICSID) had broad discretion to award costs and fees, the tribunal allocated arbitration costs evenly amongst the claimant and respondent and required each party to bear its own fees and expenses, even though the claimant prevailed. In another case where the claimant was successful on its substantive claim, the ICSID tribunal ordered the respondent to pay the claimant US$6 million for legal fees, but required the parties to bear the costs of the arbitration equally. And in still another recent investment arbitration the unsuccessful respondent was ordered to pay the costs of the arbitration, but each party was responsible for its own legal fees. These results are not unique to investment arbitrations; they can also be found in international commercial arbitrations. The lack of uniformity in the awarding of costs and fees poses two major problems. First, arbitrary awards undermine the legitimacy of the dispute resolution system. Second, the lack of predictability may hinder parties from being able to settle the dispute and could rob arbitration of its efficiency. These problems are exacerbated in the international context because the costs and fees in transnational disputes can run into the millions of dollars. Indeed, in one recent celebrated arbitration, the costs and fees totaled over US$21 million. This article examines the awarding of costs and fees in international commercial arbitrations and transnational investment disputes. My study finds that awards of costs and fees are arbitrary and unpredictable under both systems. To remedy these problems, I propose two different approaches: one for ICSID tribunals and another for international commercial arbitrations. In the case of ICSID arbitrations, the parties should share equally the costs of the arbitration and bear their own legal expenses. In essence, I propose that ICSID adopt what has become known as the American Rule with respect to the awarding of costs and fees. This approach is needed to bring predictability to the field, provide greater administrative efficiency, and reduce the overall costs. In the case of international commercial arbitrations, I argue that parties should be free to select the method for resolving claims for costs and fees, including authorizing the tribunal to resolve such claims pursuant to the principle of “costs follow the event” or the “loser pays” rule. In this context, the adoption of the American Rule would not achieve the same administrative and economic benefits, and the principle of party autonomy calls for this different approach.