Trademark infringement is a violation of the exclusive rights attached to a trademark without the authorization of the trademark owner or any licensees (provided that such authorization was within the scope of the licence). Infringement may occur when one party, the "infringer", uses a trademark which is identical or confusingly similar to a trademark owned by another party, in relation to products or services which are identical or similar to the products or services which the registration covers. An owner of a trademark may commence civil legal proceedings against a party which infringes its registered trademark. In the United States, the Trademark Counterfeiting Act of 1984 criminalized the intentional trade in counterfeit goods and services.

If the respective marks and products or services are entirely dissimilar, trademark infringement may still be established if the registered mark is well known pursuant to the Paris Convention. In the United States, a cause of action for use of a mark for such dissimilar services is called trademark dilution.

In some jurisdictions a party other than the owner (e.g., a licensee) may be able to pursue trademark infringement proceedings against an infringer if the owner fails to do so.

Section 30 of the Trade Marks Act, 199g provides limits on effect of registered trademark and also enumerates certain acts which do not constitute infringement. These acts are also used as defense in suits for infringement of trademarks