Globalization continues to intertwine the connections between people, organizations, and information, sometimes making life easier but at other times making problems more complex. The relationships between international criminal and terrorist organizations are a troubling example of this phenomenon. Groups motivated by radical ideology can fund their violent attacks through criminal means, and criminal enterprises are able to expand their influence and activities by leveraging new “customers” in terrorist organizations. This paper focuses on the nexus between trafficking and terrorism in the Balkans. First, it outlines the general similarities and differences between the two types of illicit organizations. Next, it describes the main types of trafficking—human, weapons, drugs, and contraband; and then adds antiquities trafficking to the “Big Five.” The threats posed by this complex problem set emerge through a discussion of specific examples of the nexus in the Balkans. The paper concludes by examining opportunities to disrupt the terrorism-trafficking nexus.