Ambush marketing refers to a strategy in which a business associates itself with an event, campaign, or brand without paying for official sponsorship rights. The tactic is most visible in sports, concerts, and festivals, where official sponsors have invested substantially for exclusivity. Ambush marketers may use suggestive wording, event-themed imagery, athlete endorsements, venue-adjacent promotions, or social media campaigns implying a commercial connection with the event. Common Forms of Ambush Marketing Ambush marketing typically takes one of the following forms: Direct ambushing: using event names, logos, or mascots suggesting authorization Coattail ambushing: sponsoring an athlete or broadcaster connected with the event Subtle ambushing: themed advertising, venue-adjacent campaigns, or similar visual cues The legal analysis in each case turns on whether the marketing crosses from permissible event-based advertising into infringement, passing off, deception, or wrongful exploitation of goodwill, and the risk assessment is necessarily fact-specific. Thailand has no dedicated ambush marketing statute, so legality depends on execution. A campaign that merely comments on a public event may be permissible, but one that uses protected marks, creates consumer confusion, misrepresents sponsorship status, or makes unsubstantiated claims may trigger liability under various Thai laws, as laid out below. Ambush Marketing and Thailand’s Trademark Act The Trademark Act B.E. 2534 (1991) is the primary tool for addressing campaigns that use registered trademarks, event names, logos, mascots, or confusingly similar signs. The law gives registered trademark owners the exclusive right to use their mark for registered goods, and infringement risk arises when a nonsponsor uses an event mark or a confusingly similar sign in advertising. Even referential or playful use may create liability if it causes public confusion as to sponsorship or commercial connection. The law also preserves passing-off claims for unregistered marks. This matters because event names, taglines, or mascots may not always be