The New York Times
Luckily there is an element of broad, brawny camp that prevents King Arthur from being a complete drag. Full Review
King Arthur is profoundly stupid and inept, but it's an endless source of giggles once you realize that its historical revisionism has nothing to do with archeological discoveries and everything to do with the fact that no one at Disney would green-light an old-fashioned talky love triangle with a hero who dies and an adulterous heroine who ends up in a nunnery. Full Review
Too long and too full of itself to offer more than a few fleeting moments of entertainment. It doesn't take long for tediousness to triumph.
Wall Street Journal
Bleak, remarkably turgid, tediously violent, devoid of drama, deprived of magic, stripped of romance and, except for one of the oddest boy-meets-girl scenes in movie history, a befuddled and befuddling excuse for entertainment.
The Onion (A.V. Club)
Conceptually compelling, but the interest ends there, in part because the humans get squeezed to the margins in favor of pseudo-history and clashing battleaxes. Full Review