The 25-year-old, who is regarded as one of the best forwards in European football, will be out of contract at Dortmund at the end of the season.
"I am feeling very well at Dortmund, but I want a new challenge next season," he told Sport Bild.
"I can only say one thing about my future and that's that I will announce my decision next year. No club has to bother with a fresh approach. I am focused on Dortmund and will not let anything distract me."
Lewandowski has scored 13 goals for his club this season.