Mr Corbyn posted images of himself at Theresienstadt, in the Czech Republic, on Saturday alongside the message: “Never forget.”
Mr Corbyn had earlier travelled to Prague to address leaders of left-wing parties from the continent.
Speaking to the Independent before the visit, Mr Corbyn said: “The Terezin memorial is a vital reminder of the genocidal crimes carried out during the Second World War and the dangers that far-right politics, antisemitism and racist scapegoating pose to society.
“The stories of the families incarcerated here are deeply moving and sobering. Many died of starvation and malnutrition, the cruelty and inhumanity of their treatment was unspeakable.
“We must never forget the horrific crimes perpetrated by the racist, far-right Nazi regime in Europe.”
