Birmingham bring in Bentley on loan
The 26-year-old has struggled to get regular first team football since joining Spurs from Blackburn Rovers in July 2008.
"We're delighted to have David's services. He is a classy footballer and will enhance the quality of the squad," Birmingham manager Alex McLeish told the club website on Wednesday.
"He is a natural footballer capable of top delivery at set-pieces."
Birmingham, 15th in the Premier League, take on city rivals Aston Villa on Sunday.