Pienaar returned to the team he left for Tottenham after a loan spell at Goodison Park last season.
He told the club website: “I am happy to be here. It took a few weeks to sort out but I am delighted to be back and excited to play for Everton.
“There was no doubt in my mind that I would be back here. At the end of the season I told the manager how I felt and I am happy now it is all done.”
