The threat of terrorist attacks motivates emotional reactions that elicit functional behavioral responses to characteristics of a threatening group. We argue that the more the group is seen as unjust, the more anger arises, whereas the more it is seen as powerful, the more fear arises. In Experiment 1, British participants read about terrorist groups with varied levels of injustice and power. As expected, the manipulation of injustice increased anger, and power increased fear. Anger and fear predicted offensive and defensive reactions. Experiment 2 used a representative sample of U.S. residents and again found distinct effects of an injustice manipulation on anger, and a power manipulation on fear. Anger was a primary motivator of support for offensive and defensive measures in both experiments. Willingness to negotiate was reduced with more injustice and anger, but increased with more outgroup power and fear. These findings have implications on public reactions to terrorist organizations.