Spurs seal Pienaar deal
"We are delighted to announce that we have reached agreement with Everton and Steven Pienaar for the player's transfer to the club," Tottenham said in a statement on their website.
The 28-year-old had also negotiated with Premier League champions Chelsea about a move to Stamford Bridge, but Spurs boss Harry Redknapp confirmed he had chosen to move to White Hart Lane.
"He had talks with Chelsea and he had talks with us and he has decided to come to us," Redknapp told Sky Sports News.
Pienaar joined Everton from German side Borussia Dortmund in 2007, initially on loan, before making the move permanent a year later.
His Everton contract was due expire at the end of the season and he rejected the offer of an extension.
Everton said on Monday they had accepted an offer from Tottenham for Pienaar, who missed Sunday's Merseyside Derby against Liverpool following confirmation that a bid from Chelsea had been accepted.
He has made 20 appearances this season, scoring a solitary goal against Manchester United in September.