The Knights who say "Ni" are a fictional band of knights from the film Monty Python and the Holy Grail, feared for the (fairly ludicrous and surreal) manner in which they utter the word "ni" (pronounced "nee"). See T-V distinction for a discussion of the Swedish word "Ni" that lies behind this joke.

The Knights are led by a man who is approximately 12 feet tall, with disproportionately short arms and has tree branches inserted into his helmet (in reality, the part was played by Michael Palin standing on a ladder, almost unrecognisable under a helmet). The other knights are of normal human dimensions and act as a chorus, only repeating words and phrases which the head knight has spoken.

"Ni" is only the most notable of the sacred words which they are assigned to protect; the others are "Peng" and "Neee-wom". All are infamous for the palpable horror and fear they bring about, whether delivered by the Knights or not.

The knights demand that King Arthur buy them a shrubbery in order to pass through a patch of woodland which they guard. Later, they become the Knights of an unspellable string of characters. The unspellable saying could be spelled this way:

Ecky-ecky-ecky-ecky p'kang! Zroop-foybin! zowzim...

with the last word mumbled. (It is easier to call them "The Knights who until recently said Ni" now). Originally, the name was to be changed to the Knights Who Go Ni...Wom...Peng.

Then they demanded that King Arthur get them another shrubbery, arrange the two shrubberies so that they get a two-level effect (with a little path running down the middle), and cut down the tallest tree in the forest with a herring.

The Knights who say "Ni" have a weakness, in that a number of words, when spoken to them, cause them pain and agony. The only one of these words that is revealed in the film is the word "it".

NOTE: There was a further scene that was scripted, but either cut or never filmed. In it, the Knights recover from having "it" said, and when they hear someone else coming, they decide that they'll demand another shrubbery, this time calling themselves the "Knights of Nicky-Nicky".