A war exclusion is a provision found in nearly all insurance policies that excludes loss arising out of war or warlike actions.
The loss can result from either declared or undeclared war but must be related to actions of a military force directed by a sovereign power. Prior to the September 11, 2001, terrorist attacks, the war exclusions in most liability insurance policies applied only with respect to contractually assumed liability, on the theory that private persons and organizations could not otherwise incur liability in connection with war. Following the September 11, 2001, terrorist attacks, "war and terrorism" exclusions that broadened the war portion of the exclusion beyond contractually assumed liability, were quickly added to liability policies. That broadened war exclusion is now standard, regardless of whether terrorism is insured or excluded in the policy.