This book explores how and to what extent investment treaty tribunals scrutinise, assess and balance states' public acts, and compares it to judicial review.It evaluates whether the approaches adopted by investment treaty tribunals resemble judicial review in public law or are influenced by approaches in private law or customary international law. The book also analyses new generation treaty texts, and how tribunals approach their review, to assess any effects on the tribunals' own review approaches. The analysis combines a broad set of contemporary awards from 2015 to date, with judicial review performed by public courts, claims tribunals, and commercial arbitral tribunals. It shows that, contrary to the high level of scholarly interest and promotion of public law methodologies, investment treaty arbitration displays limited development towards public law-oriented review approaches. The book suggests that states contribute to maintaining the established practice founded on customary international law by failing to provide tribunals with a clear mandate to apply public law methodologies or to balance opposing interest in new generation treaties. This makes it challenging for tribunals to change their review approaches.Judicial Review in Investment Treaty Arbitrationis an essential resource for those wishing to understand in what way and to what extent investment tribunals review states' public acts and balance state interests.