STORY: Google faces damages claims of up to $25.4 billion in the coming weeks.
The Alphabet-run search giant is accused of unfair advertising practices.
The two suits are due to be filed in British and Dutch courts.
A law firm said on Tuesday (September 13) that Google should pay back the damages it has caused to EU and UK publishers.
Antitrust regulators have investigated Google's advertising technology recently after complaints from publishers.
The European Commission and the UK want to see whether the adtech business gives Google an unfair advantage over rivals and advertisers.
Google criticized the lawsuits, and said it worked constructively with publishers across Europe.
The British claim will aim to recover compensation for all owners of websites carrying banner advertising.
The Dutch claim is open to publishers affected by Google's actions.
Alphabet's Google has been hit by large fines in Europe recently.
Last year, the French competition watchdog hit it with a 220 million euro penalty.