Although the “passing off” principle has sometimes faced criticism for potentially broadening trademark protection—particularly in cases involving unregistered or unconventional marks like shapes, scents, or sounds—it serves an essential purpose. It safeguards the rights of business owners and shields consumers from deception, ensuring fair competition and reflecting the realities of modern commerce.

What is passing off, and why is registrability not required?

The passing-off principle is a legal concept rooted in English law, aimed at preventing a person from falsely representing or using a mark similar to another’s in a way that causes consumers to mistakenly believe the goods or services come from the same source.

Under Thai law, the passing-off principle is provided under Section 46 of the Thai Trademark Act, which states:

No person shall be entitled to bring legal proceedings to prevent or to recover damages for the infringement of an unregistered trademark.

The provisions of this Section shall not affect the right of the owner of an unregistered trademark to bring legal proceedings against any person for passing off goods as those of the owner of the trademark.

The passing-off principle can be interpreted as a practical legal concept. It does not require proof that the mark is registrable or meets the registrability criteria under trademark law. It is sufficient to show that the mark has established goodwill and that the other party’s use of a similar mark is likely to confuse consumers, making it a straightforward and effective tool for protecting brand assets.

Requiring a claimant to prove that an unregistered mark could have been registered would undermine the very function of passing off. The doctrine was conceived precisely to fill the gaps left by the registration system. Imposing registrability criteria would nullify its function and leave many commercially valuable identifiers unprotected.

If the doctrine of passing off were not rigorously enforced to safeguard a proprietor’s rights, a third party could unlawfully exploit the proprietor’s goodwill and reputation. Such bad-faith conduct would primarily harm consumers, who would be misled into believing that the infringer’s goods originated from, or were otherwise affiliated with, the rightful owner. Inevitably, the quality of those infringing goods would fail to measure up to the high standards consistently maintained by the legitimate proprietor.

Moreover, many nontraditional identifiers, such as distinctive store layouts, packaging designs, or color schemes, may not qualify as registrable marks under statutory law. However, these identifiers often acquire significant consumer recognition and goodwill. Excluding them from protection would ignore the commercial realities of how consumers identify and differentiate products.

Even where a product’s configuration represents its natural form or is dictated by functional necessity, that shape may nonetheless be eligible for trademark protection if the proprietor has expended substantial resources to promote the design and, as a result, the consuming public has come to recognize the configuration as identifying the source of the goods—that is, the shape has acquired distinctiveness, or secondary meaning.

Judicial decisions supporting the passing-off principle

Thailand’s Supreme Court established in Decision No. 343/2503 that if a trademark is not registered but has been used continuously and has gained popularity and recognition among consumers, it can be protected under the passing-off principle, without the need to prove it meets registrability requirements under the Trademark Act.

Various judgments of the Central Intellectual Property and International Trade Court have also held that the passing-off principle can be applied to unregistered marks without the need to prove that the mark is considered registrable under Thai law. This emphasizes that protection under the passing-off principle aims to prevent consumer deception and maintain market integrity, providing a secure legal framework for your business interests.

Conclusion

Strictly interpreting the passing-off principle by adhering to registration criteria may deprive longtime business owners who have used their marks but have not registered them of rightful protection, despite their legitimate interest in safeguarding their reputation and consumer trust. Nontraditional identifiers like trade dress, including store layouts, packaging designs, and color schemes, should be recognized as protectable when they have acquired distinctiveness or serve the function of a trademark. Businesses that have invested time and resources in building goodwill deserve legal protection even if their marks are not registered or not qualified for registration by law. Denying such protection would undermine both commercial fairness and consumer confidence, especially when the law does not require registration for enforcement under the passing-off principle.