Can social image concerns cause people to take costly actions benefiting their community? Using newly collected data, I study the impact of public shaming on voluntary recruitment during World War I in England and Wales. At the time, young women in many towns and cities handed out white feathers to men in civilian clothes, marking them out as cowards. This was intended to encourage volunteering. I reconstruct a panel of “White Feather Girls” activity from local newspaper articles and exploit the staggered spread of the movement in an event study framework. Following episodes of public shaming, recruitment increased significantly: Volunteering surged by a third during the 10 days after the first mention of the White Feather Girls in the news. Confounding factors such as reporting of wartime events are unlikely to account for these patterns. These results suggest that public image concerns can have first-order effects on costly altruistic behavior that benefits the group.