The 19-year-old winger, who has impressed with the Reds senior side during pre-season, will spend the 2016/17 season with the Tykes at Oakwell.
Kent made his senior debut for Liverpool last season against Exeter City in the FA Cup in January following a loan stint with Coventry City where he coincidentally scored his first and only senior goal to date against Barnsley.
Manager Paul Heckingbottom told the South Yorkshire outfit's official website: "We first enquired about Ryan last summer and we've continually monitored his progress, so I'm absolutely delighted to have him as part of our squad for next season.
"We saw a lot of him last season and he made a huge impression at Coventry.
"He's one of the most highly rated youngsters in the country and now he has a great opportunity to step up and show us what he can do in the Championship.
Happy To Have Signed A Loan Deal With @bfc_official / Looking Forward To The Start Of The Season https://t.co/poYFTPr65W
— Ryan Kent (@ryankent) July 26, 2016