Trademark

If you were asking about needing to register in the U.S., you have a great answer. If you are asking about the need to register in other countries, consult lawyers licensed to practice trademark law in the countries in which you are interested. Trademark law is territorial and only extends to the borders of the country unless your registration is with the European Union, which covers all 27 member nations, or another multi-country treaty (like between Belgium, Netherlands and Luxembourg).