The world faces an immigrant humanitarian crisis, partly driven by the thousands of Central Americans in Mexican territory heading to the United States. One of the most pressing challenges in addressing this crisis is how to improve citizens’ attitudes toward immigrants. While emerging research has explored this question, we still know little about the kinds of interventions that promote support for immigrants. Partnering with one of the largest humanitarian organizations in the world, we examine how media campaigns that seek to build empathy towards Central Americans in Mexico can reduce prejudice and discrimination and promote support for pro-immigrant policies and altruistic behavior. We assess the effectiveness of the humanitarian organization’s media campaigns through three survey experiments to identify design features (e.g., the types of narratives and the characteristics of the messenger) that yield the most positive and durable attitudinal and behavioral changes.