Sydney fashion designer Katie Jane Taylor won a legal battle against Katy Perry and her companies over the right to use her name.

The battle started over a decade ago when Taylor received legal documents opposing her trademark and demanding she stop the sale of her clothes and advertising material.

Katy Perry threw in the towel before the dispute went to court but her company, Kitty Purry, introduced her clothing range into the Australian market.

Taylor decided to fight back to show her children to stand up for what is right.

Perry took the battle to the Federal Court, which ruled in Taylor's favour.

It is unclear how much Kitty Purry will need to pay in damages.

The legal battle has cost many hundreds of thousands of dollars, if not millions.

Overseas conglomerates often bully and intimidate small businesses with legal jargon.

Taylor is willing to forgive Perry but won't forget.

She wants to go back to focusing on the future.

Lawyer Richard Mitry said Perry may appeal the decision.