Missile Threat Reduction Act of 2003 - Amends the Arms Export Control Act to increase the duration of existing sanctions against foreign persons who violate U.S. export controls with respect to the transfer of missile equipment and technology on the Missile Technology Control Regime (MTCR) Annex. Requires sanctions imposed under the Arms Export Control Act and the Export Administration Act of 1979 to extend to governmental entities and other entities, including transactions involving third parties.
Authorizes foreign assistance and technical assistance to countries that agree to destroy their ballistic missiles.