||The current research tests two alternative hypotheses surrounding the structure of terrorist networks. First, some argue that terrorist networks exhibit string-like structures of sparse connections as an effort to maximize operational security. Others maintain that terrorist networks tend to contain a few highly-connected individuals who play crucial roles in connecting the greater network. Using dynamic stochastic actor based (SAB) models, we test both of these hypotheses on ten multi-wave networks of terrorists who carried out prominent attacks or bombings during the twenty-first century (e.g., the 2002 and 2005 Bali Bombings, the Australian Embassy bombings of 2004). Results suggest that, in contrast to theories about maximizing operational security, most terrorist networks are relatively well-connected. We also find evidence that terrorist networks tend to be structured around a couple of key actors who receive particularly high numbers of relational ties. In future analyses, we plan to further consider the structural characteristics of terrorist networks by comparing networks that carry out different types of terrorism (e.g., attack vs. bombing) and based on the severity of the event. Our findings have the potential to inform strategies of counterterrorism efforts by suggesting which actors in the network make the most impactful targets.