This report presents findings from the first interview survey of witnesses who have appeared before the International Criminal Court (ICC or the Court). The survey examined the opinions and attitudes of 109 individuals — ranging from victims to expert witnesses — who testified in the Court’s first two trials — Prosecutor v. Thomas Lubanga Dyilo and Prosecutor v. Germain Katanga. Both trials took place in the Court’s chambers in The Hague and concerned serious international crimes that occurred in the Democratic Republic of Congo between July 2002 and December 2003. A total of 123 witnesses testified in both trials.