Peacekeepers are widely viewed as being at growing risk of deliberate violence. Attacks are recorded in diverse contexts, targeting peace operations implemented by the UN and other deploying bodies. Such incidents can carry grave personal costs for those immediately affected but may also adversely impact interveners' ability to operate effectively and deliver on their mandates. Concerns of rising threats have led to growing attention to peacekeepers' safety and security in policy-circles. As a topic of scientific inquiry, however, violence against peacekeepers has only recently seen a growth in interest, and systematic study has so far been sparse. This chapter reviews theoretical and empirical advances in this emerging area of research. To do so, it distinguishes two main sets of research on the topic: one set oriented toward exploring patterns and trends, and one devoted to explanation. The chapter concludes by outlining possible directions for future research.