Naughton had been linked with a loan move to Portsmouth but instead links up with Leicester ahead of Saturday's Championship clash with Hull.
The former England Under-21 international joined Tottenham along with Kyle Walker from Sheffield United just over a year ago and spent the second half of last season on loan at Middlesbrough.
The 21-year-old has made just one first-team appearance for Spurs this season - in the Carling Cup defeat to Arsenal - and four in total.
Eriksson insisted earlier this week he would not rush into the transfer market as he seeks to get Leicester back into the Premier League, but he has moved quickly to capture Naughton.
Eriksson succeeded Paulo Sousa earlier this month and has been assured by the Thai consortium now in control at the Walkers Stadium that they are prepared to bankroll a promotion push.
As well as Naughton, Eriksson has been linked with Fulham's Fredrik Stoor and Blackburn's Jason Roberts.