Louis Theodor Kipp (7 March 1862 – 2 April 1931) was a German jurist who is perhaps best known for his theory of "double nullity", under which a null contract can be challenged in some circumstances.

He earned his doctorate in 1883, was admitted as a lawyer in Leipzig in 1887, and obtained a position as an associate professor at the University of Halle.

[1] In 1914 Kipp was one of the signatories to the letter "To the Civilized World" signed by 93 German professors, known as the Manifesto of the Ninety-Three, in which the signatories disclaimed responsibility by Germany for starting World War I (1914–18), denied improper action by Germany in invading Belgium, and denied violation of international law.

[2][a] Kipp published a history of the sources of Roman law in 1896, which ran into several editions.

[5] Kipp is best known for his theory of "double nullity", where a contract that is void for some reason could still be challenged.