Despite record numbers of internally displaced persons (IDPs) globally, there are few experimental tests of the causal effects of intergroup contact in active conflict settings, and even fewer with migrant outgroups. We evaluate a randomized controlled trial of a vocational skills training program conducted by Mercy Corps that enrolled 2,597 locals and migrants in near equal numbers in Kandahar, Afghanistan, where IDPs face daily prejudice and discrimination. Courses lasted three or six months and emphasized collaborative learning and soft skills development. We conducted an endline survey and followed up eight months later. While the program provided the most sustained duration of intergroup contact (360–720 hours) experimentally evaluated to date, we find no evidence of reported behavioral or attitudinal change by locals toward IDPs, regardless of classroom demographics or course duration. Our findings suggest that migrant status is a relevant identity cleavage, and in conflict settings, contact is likely insufficient to improve relations.