Assou-Ekotto, 25, was tipped to leave White Hart Lane last year but has established himself in Redknapp's team and is ahead of Gareth Bale in the pecking order at Spurs.
On Sunday he scored the spectacular opener in the victory against Liverpool, his first for the club more than three years after being scouted by Damien Comolli at Lens.
"He has done very well,'' Redknapp said at the end of last season. "He was injured last year but I have been very impressed with him as he has been in great form. He has looked an outstanding left-back.''
His form earned the French-born player his first caps for Cameroon earlier this year and, with his current deal believed to expire at the end of the campaign, a fresh contract.