The 23-year-old returns to The Valley after spending the second half of last season with the relegation-threatened Championship club - scoring three goals in 10 appearances.
Most recently, the former England Under-20 international spent time on loan at Brighton and Hove Albion but will become the first arrival of the Jose Riga era.
"The striker has been recalled from his loan spell at Brighton, where he made seven appearances, to return to The Valley where last season he made 10 appearances, scoring three goals," read a statement onTottenham's official website.
Obika has yet to feature in the Premier League for the London club, but Riga will hope he can produce the goods and help keep Charlton in the second tier.
Chartlon held Millwall to a goalless draw on Saturday and sit 22nd in the table with four games in hand on some of their fellow strugglers.
