Trademark law, generally, has three primary areas of defense. The first category of defenses are standard equity defenses, and the second category of defenses are first amendment defenses. The final category of defenses are not exactly defenses, per se, but assertions that the alleged trademark owner has lost the protection of their trademark. See loss of trademark rights for more information regarding this category of defenses.

Of course, one must keep in mind there are other defenses inherent in trademark law. For example, one must prove a valid right and the defendant's violation of the right to even successfully assert a valid trademark claim.

At times, an alleged infringer may also assert an anti-trust defense, but this type of defense is beyond the scope of this article.