Most patent laws around the world impose restrictions on filing patent applications abroad for inventions made domestically, in that country, or for inventions made by its residents or nationals. This is primarily for national security reasons. Applicants may be required to file their first patent application in the relevant country, or at least obtain a foreign filing license. This situation can be complicated when multiple countries have an interest in an invention.

Foreign filing violations can result in criminal penalties or loss of patent rights. Patent counsel should also consider their ethical duty of candor before tribunals.