Supporters in the popular fancy dress costume of chainmail and a large St George's cross tunic may be misinterpreted as being 'crusaders' - a term Islamic State uses to describe its enemies in the West.
Chris Doyle, director of the Council For The Advancement of Arab-British Understanding, warned the harmless costumes could cause offence to some.
He told the Daily Star : "England fans will go out to France and have fun and dress up,” he said.
"I'm sure they intend no ill will and I don’t think one should expect them to be
aware of historical and cultural connotations."
Earlier this week a plot by ISIS terrorists to target England fans during Euro 2016 was discovered by police.
The fanatics were planning to use suicide bombers, guns and even drones carrying chemical weapons to attack Three Lions fans in Marseille.
Police have revealed they have found data on a laptop used by Salah Abdeslam, suspected mastermind of the Paris and Brussels attacks, outlining a plan to target England supporters as they gather in the city for the June 11 clash with Russia.
Read more: Three arrested for 'plotting ISIS suicide bomb terror attack in Dusseldorf'
It is feared followers of Abdeslam are determined to carry out the attack despite his capture.
In January ISIS released a video of the Paris killers speaking from beyond the grave shows how the terror group considers its enemies as 'crusaders'.
One Arabic passage in the video, with translated French subtitles, says:“We tell you, oh crusaders, safety will be nothing more than a dream as long as you call airstrikes upon Muslims on the lands of the Caliphate.
"If you do not put an end to this coalition, then by the will of Allah, we will fight you from within the heart of your lands."
The crusades were a series of military campaigns waged by Christian nations in the Muslim-dominated Holy Lands beginning in the 11th Century.