Do men and women respond differently to negative political communication? Only a limited collection of studies into the effects of negative campaigns have investigated this research question, and the conflicting results produced from such studies have prevented the development of a widely accepted answer. As campaigns transition to new media environments, further problems arise, as any potential gender gap may be magnified on the new political communication battlefield of social media. The present article contributes to this sparsely investigated area through an empirical study of men's and women's reactions on Facebook to US presidential candidate attacks during two general election campaigns (2012 and 2016) and two primaries (2016 Democratic and Republican). Across nearly 400 million reactions and 40 million unique users, women demonstrate lower receptivity to candidate attacks than men. Two potential explanatory factors for the gap are examined, but neither fully captures the magnitude of the differences observed. Conceptualizing the gender gap composition in terms of differential receptivity most accurately explains these findings and potentially resolves the competing explanations for the gap within the existing literature.