The film was inspired by Don Mullan's politically influential book Eyewitness Bloody Sunday (Wolfhound Press, 1997).

The march ended when British Army paratroopers fired on the demonstrators, killing thirteen and wounding another who died four and a half months later.

In recognition of the role his book played in achieving the new Bloody Sunday Inquiry, his book's role as inspiration for the movie, and the fact that he was a schoolboy witness to the tragedy, Don Mullan was asked by director Paul Greengrass to appear in the film as a Bogside Priest.

The site's consensus reads: "Bloody Sunday powerfully recreates the events of that day with startling immediacy.

"[5] Metacritic, which uses a weighted average, assigned the film a score of 90 out of 100 based on 31 critics, indicating "universal acclaim".