Protection Against Terrorist Hoaxes Act of 2003 - Amends the Federal criminal code to set criminal and civil penalties for using the mail, telephone, telegraph, or other instrument of, in, or affecting interstate or foreign commerce to knowingly engage in any conduct that is likely to impart the false impression that activity is taking place, or will take place, that violates provisions regarding biological or chemical weapons, nuclear materials, or weapons of mass destruction.

Makes a violator of such civil offense liable to the United States or any State for a civil penalty of the greater of $10,000 or the amount expended by the United States or the State in responding to the false information.

Directs the court to order a defendant who has been convicted of such a criminal offense to reimburse the United States or a State for any expenses incurred incident to the investigation of the offense, including the cost of any response made to protect public health or safety. Makes such person jointly and severally liable for such expenses with each other person ordered to reimburse the United States or any State.