Adolph Franz Friedrich Ludwig Freiherr Knigge (16 October 1752 – 6 May 1796) was a German writer, Freemason, and a leading member of the Order of the Illuminati.

He was allegedly initiated into Freemasonry in 1772 in Kassel, where he held a position as Court Squire (hofjunker) and Assessor of the War and Domains Exchequer.

Knigge stated that he could no longer endure Weishaupt's pedantic domineering, which frequently assumed offensive forms.

"And was I", he adds, "to labour under his banner for mankind, to lead men under the yoke of so stiff-necked a fellow?—Never!"

In Germany, Knigge is best remembered for his book Über den Umgang mit Menschen (On Human Relations), a treatise on the fundamental principles of human relations that has the reputation of being the authoritative guide to behaviour, politeness, and etiquette.