This thesis provides insight into how terrorist organizations exploit the information environment to achieve their objectives. The study establishes an analytical IO framework, by integrating US military doctrine with a fundamental approach to IO theory. The framework proves useful in examining the IO tools terrorists have assembled and how they implement them to influence their target audiences. The thesis shows that terrorists are, indeed, naturally linked to the information environment by their nature and strategy. Generally speaking, all terrorists employ IO tactically to enhance their operations. However, many organizations have a profound understanding of the information environment and also have the ability to manipulate information to achieve their objectives. Since, terrorist organizations are militarily weaker than the states they face and cannot rely on physical attacks to accomplish their goals, they must adopt an information strategy to achieve their objectives. This thesis emphasizes three primary conclusions: first terrorist conduct violent attacks in the physical environment to enable operations in the information environment. Second, terrorist integrate offensive and defensive IO to survive and appear legitimate to potential supporters and to the state. Finally, terrorists intentionally target four different audiences: opposing, uncommitted, sympathetic, and active to influence their perceptions.