Police have launched an investigation and are examining CCTV footage to see if they can identify the person involved, while Spurs have also agreed to help the police with their enquiries.
Bale is sometimes targeted by opposing fans, who often make derogatory chants about the appearance of the Wales international.
"Police are investigating after a banana was thrown on to the pitch from the away section of supporters during the Tottenham Hotspur v Arsenal match at White Hart Lane on Sunday March 3rd," said a Met Police spokesperson.
"There have been no arrests. Enquiries continue to try to identify the suspect."