The match, scheduled to kick off at 7.30pm at the King Power Stadium in Leicester, is now the fourth top-flight fixture to be cancelled in the last week.
Thousands of fans were expected to attend tonight's Premier League game at the King Power Stadium.
Leicester City Football Club (LCFC) said further positive Covid tests this morning mean they have an "insufficient number of First Team players available to fulfil the match".
"The club regrets the inconvenience caused to Tottenham Hotspur and both sets of supporters by Thursday night’s postponement," it adds.
Both managers confirmed last week they had multiple cases among their players and staff, with Tottenham closing their training ground for five days.
In a statement, LCFC said: "The decision was taken with guidance from medical advisors after the Club resubmitted its application for postponement after confirmation this morning of further positive tests for Covid-19 within the first team squad.
"As a result, the Club has an insufficient number of First Team players available to fulfil the match.
"Given the increase in positive tests among First Team personnel, First Team operations at Seagrave will now be closed for 48 hours, serving as a circuit breaker to help reduce the risk of further infection.
"First team players and staff will undergo a subsequent round of testing on Saturday.
"The Club regrets the inconvenience caused to Tottenham Hotspur and both sets of supporters by Thursday night’s postponement."