The Belgian international endured a difficult first campaign with Spurs last season following a £7m move from FC Twente.
However, the 26-year-old has enjoyed a resurgence so far this term, scoring two goals in three games for the North London outfit.
"I am looking forward and with the new manager coming in, it has given me another chance," Chadli told the club's official website. "We all know what we have to do on the pitch and what it takes to play in the Premier League."
Chadli featured for his country on Thursday night during their 2-0 friendly win over Australia.