Wimmer moved to Spurs from Cologne last summer and enjoyed an impressive run in the side while first-choice centre-back Jan Vertonghen was injured.
The Austrian's new deal extends his commitment at White Hart Lane by one year.
A Tottenham club statement read: "We are delighted to announce that Kevin Wimmer has signed a new contract with the club until 2021."
Wimmer made 21 appearances in all competitions last term and was particularly assured during a spell of nine consecutive starts in the second half of the season.
Vertonghen was recalled to the starting line-up when he returned but with the Belgian now expected to be out until September with an ankle injury, Wimmer is likely to start the campaign at the heart of Tottenham's defence.
The 23-year-old has earned four caps for Austria and came on as a substitute during his national side's goalless draw with Portugal at Euro 2016.
Source : PA
Source: PA