In national courts, it is generally assumed that local judges are best placed to adjudicate and resolve disputes that arise. This reflects a combination of related concerns surrounding sovereignty, domestic legal expertise and a sociological conception of legitimacy that posits that the judiciary should reflect the society within which it operates. Against this background, the use of foreign judges may be regarded with various degrees of scepticism and alarm. This chapter reflects on these concerns by considering the development and practice of hybrid criminal tribunals. Comprising a combination of both local and foreign judges, hybrid criminal tribunals have been established in several states across the world, including Sierra Leone, Lebanon, Bosnia and Herzegovina, Cambodia, and the Central African Republic. This chapter develops our understanding of comparative judicial practice by exploring the history, justifications and challenges of these unique courts.