Trademark opposition is a legal process by which a third party can challenge the registration of a trademark application filed by another party with a trademark office. The opposition process allows the third party to raise objections to the trademark application, with the goal of preventing the registration of a trademark that may conflict with their own rights or interests.

The opposition process varies from country to country, but generally involves filing a notice of opposition with the relevant trademark office within a certain timeframe after the publication of the trademark application. The third party must then provide evidence and arguments to support their opposition, and the trademark owner has an opportunity to respond.

The trademark office will then consider the opposition and any evidence provided by both parties, and make a decision on whether to allow or refuse the trademark registration. If the trademark registration is refused, the trademark owner may appeal the decision, and the opposition process may continue in court.

Trademark opposition can be an important tool for protecting intellectual property rights and preventing confusion or unfair competition in the marketplace. It is important for businesses to monitor trademark applications and take prompt action if they believe that a trademark registration may infringe on their own rights.