The 21-year-old has signed a two-and-a-half-year deal with the Reds after an undisclosed fee was agreed with League Two leaders Wycombe.
A midfield lynchpin, Scowen has been an integral part of Gareth Ainsworth's side this season as the Adams Park outfit sit atop of League Two.
New signing Josh Scowen with Reds Chief Exec Ben Mansford this evening
Speaking to barnsleyfc.co.uk, Reds boss Danny Wilson said, "We've identified what we feel is one of the best players in the division. He's highly regarded by his team-mates and those he's played against this season.
"We're looking forward to working with him. He gives us tenacity and adds strength to the team. Looking at him, he's got the heart of a lion - that's what we need and what we want."
Scowen has made 100 appearances for Wycombe and is hopeful of featuring this weekend at Doncaster Rovers.
