The fast food chain sent a push alert to users of its app in Germany on Wednesday, saying: "It's memorial day for Kristallnacht! Treat yourself with more tender cheese on your crispy chicken. Now at KFCheese!"
Known in Germany as ‘Reichspogromnacht’, Kristallnacht saw 90 people killed and Jewish businesses destroyed by Nazi forces in 1938.
KFC apologised an hour later, saying the mistake was made due to its automatic advertising being linked to a calendar that lists national celebrations and observances.
"We understand and respect the gravity and history of this day, and remain committed to equity, inclusion and belonging for all," the statement said, adding the company had suspended its app push notifications while it investigated the incident.
Daniel Sugarman, director of public affairs at the Board of Deputies of British Jews, described the original KFC message as "absolutely hideous". He said it had outdone Scottish brewery Brewdog in terms of a marketing blunder.
Brewdog earlier this week came under fire from customers after it released a series of adverts styling itself as the “anti-sponsor” of the World Cup in Qatar, due to the country’s human rights record – but is still to show the tournament’s games in its bars.
Mr Sugarman said: “In a successful attempt to outdo Brewdog in the ‘worst marketing blunder of the month’ stakes, KFC Germany reportedly sent out a push notification offering customers special chicken deals for Kristallnacht, before sending out another message apologising. Absolutely hideous.”