The Trademark Act of Thailand of 1991, amended by the Trademark Act (no.3) of 2016, regulates the registration and protection of trademarks, service marks, collective marks, and certification marks.

A trademark is a symbol adopted or used by a manufacturer or merchant in order to identify specific goods and to distinguish them from those manufactured or sold by others.
To be registrable, a trademark must be distinctive, not be prohibited by the Trademark Act, and not be identical or confusingly similar to another registered trademark in the same class.

Certain marks are explicit prohibited by law because include:
• Elements contrary to public order, morality or public policy
• Royal or official arms, crests or flags
• Representations of members of the Thai royal family
• Geographical indications protected under the law on geographical indications
• Elements identical or confusingly similar to a well-known mark

In Thailand is possible to file a single-class or a multi-class application. The multi-class application system was introduced to meet the requirements of the Madrid Protocol, a central registration system for the international registration of trademarks and service marks via a single application.
The primary benefit of a multi-class application is the convenience offered by a single filing application covering all classes for which registration is sought.
Despite the convenience a multi-class application may offer, difficulties can arise if the registrar has objections or opposition to registration in some classes, but not others. Under the current practice, any objections raised against one particular class will cause delays to all other classes as the registrar will not allow the separate prosecution of those classes for which no objections were raised. Likewise, if any class encounters absolute rejection grounds, the whole application will be rejected and it will be necessary to file an entirely new application covering all other classes for which no rejection grounds were raised, meaning delays and added expense.

Trademark owners have now much more flexibility in assigning their marks. Marks of the same owner covering goods of the same class or different classes but of the same character and which are similar to one another don’t have to be registered as associated marks.

The representation of forged or imitated trademarks on the goods’ packaging with the intention of making the people believe that these goods are goods of another person is completely prohibited by law. In addition, the law prohibits any person from using packaging that displays another person’s trademark for their own goods or a third party’s goods to make the public believe that they are the goods of the registered trademark’s owner. If these persons made this intentionally, they will be liable to imprisonment of up to 4 years and/or a fine of no more than 400,000 Baht.