Do trademark registration rules differ between countries?

The general rules applicable for the registration of a trademark do not vary between countries.

The primary criteria a trademark application has to meet to be registered are distinctiveness (uniqueness) and difference in relation to previously filed/registered trademarks. These criteria are consistent across all jurisdictions.

What's also universally shared is the division of the process into two stages: the examination period and the opposition period. During the examination period, the IPO evaluates the above-mentioned criteria and other formal requirements. Once the application is approved, it will be published for opposition, where the owners of other already registered trademarks can oppose your application. However, the length of these stages tends to vary between countries.

The thoroughness of assessment by an intellectual property office can also differ and is generally related to the number of trademark applications that are filed in the country of registration. For example, since more trademarks are filed in the US and China than in the rest of the world, the examination by their respective IPOs is more thorough than in Spain or Norway, for instance.

Countries also divide into 'first-to-use' and 'first-to-file' depending on how they grant priority rights. First-to-use countries give rights to the first entity to use the mark in commerce, first-to-use to the entity filing the application the soonest.

The US deserves a special mention here since it features a few process differences, including dividing marks into already used in commerce/intended to be used in commerce and requiring the submission of a specimen of use.