Gunners players were left incensed after referee Graham Scott gave Leicester a 75th-minute spot-kick for a foul by Henrikh Mkhitaryan on Demarai Gray at the King Power Stadium.
Jamie Vardy converted the penalty to put Leicester 2-1 up and on course for victory in Arsenal’s penultimate game of the Premier League season on May 9.
“Arsenal have been fined £20,000 after failing to ensure their players conducted themselves in an orderly fashion during the 75th minute against Leicester City on 9 May 2018,” an FA statement announced.
“Arsenal admitted the charge but did not accept the standard penalty. An Independent Regulatory Commission subsequently ruled that the circumstances were not truly exceptional and the fine was applied.”