The 19-year-old is in line to make his debut as early as tomorrow when the Whites visit Barnsley to try and avenge a number of defeats on the bounce at Oakwell.
Barkley has already spent time on loan in the Championship this season after a spell at Sheffield Wednesday. During his time at Hillsborough he made 13 appearances scoring four goals.
The midfielder is currently playing for the England U-21's and is thought to be one of the top prospects at Everton.
Speaking to the official site, Neil Warnock said:
"I'm absolutely delighted to get Ross and I'd like to welcome him to the club. He had four other clubs after him so I'm delighted he's come to us.
"I've wanted to sign him for a long time now, I remember watching him when he played for Everton against QPR in the Premier League. He's got a great attitude and I have no doubt that he will end up a top player.
"The deal works well for both parties as he will gain experience here and he is a great addition to our squad."