Letter of Consent (Trademarks)

Letter of consent in trademark law refers to a written declaration by the owner of an earlier trademark consenting to the registration or use of another trademark that may otherwise conflict with its rights.

Letters of consent are commonly used to overcome refusals, oppositions, or coexistence concerns based on likelihood of confusion between similar trademarks. The document typically confirms that the earlier rights holder does not object to the registration or use of the later mark under agreed conditions.

The legal effect and acceptability of consent letters vary between jurisdictions. Some trademark offices and courts may accept letters of consent as evidence reducing the risk of confusion, while others may still independently assess public interest and consumer confusion considerations.

In Türkiye, letters of consent are recognized under the Turkish Industrial Property Code and may be used in certain cases to overcome relative grounds refusals before the Turkish Patent and Trademark Office.

Letters of consent are frequently used in trademark coexistence arrangements, settlement negotiations, international trademark filings, and portfolio management strategies.