The US Olympic and Paralympic Committee is suing Logan Paul and KSI’s Prime energy drinks brand, accusing it of trademark infringement.
It claims that Prime is using trademarked Olympic phrases and symbols on a special edition of its hydration drink featuring basketball star and three-time Olympic gold medallist Kevin Durant.
The committee said it does not have an agreement with Prime for the use of its terminology and trademarks, and said its actions had been deliberate and in bad faith.
The BBC has contacted Prime for comment.
The committee filed the lawsuit in Colorado on Friday, and also accused Prime of using the trademarks in internet campaigns and promotions.
The lawsuit said consumers could be misled into thinking there is an agreement between the US Olympic and Paralympic Committee and Prime.
The organisation said it had issued a cease and desist letter to Prime, but the drinks brand had continued to market the product, using the branding.
Criticism has previously been levelled at the company due to it being marketed at a younger audience, with some schools in the UK issuing warnings or choosing to ban it.