While developing the plot for Batman: Arkham Knight, Warner Bros. Games concluded from a ratings analysis that certain scenes would cause "issues", so they requested a Mature rating from the Entertainment Software Ratings Board. Rocksteady Games founder Sefton Hill was initially surprised and scared by this, as the game didn't include "gratuitous blood or swearing" and he believed the rating would take away the team's creative freedom. After a phone call with WB Games' vice president of production Ames Kirshen calmed these fears, Hill agreed to go forward with the M rating.

The rating was likely triggered by scenes such as the player as Batman interrogating a Militia grunt by using the wheel of the Batmoblie to torture him for information, the Professor Pyg sequence with blood being splattered all over the room, and unarmed characters being shot in cutscenes and while playing as Spoiler:the Joker. Hill was aware that this meant certain people would not be able to play the game, but he stated that he didn't want to compromise any of the game's content despite not writing the game with that rating in mind.