Louis Théophile Joseph Landouzy (27 March 1845 – 10 May 1917) was a French neurologist from Reims, and whose father and grandfather were also physicians.
His name is associated with the "Landouzy-Dejerine syndrome", a type of muscular dystrophy with atrophic changes to the facial muscles and scapulo-humeral region.
It is named along with neurologist Joseph Jules Dejerine, who was a colleague and close friend.
Landouzy's primary area of interest dealt with tuberculosis, and he was a major figure involving education of the public for its eradication.
He is credited with coining the word "camptodactyly" to describe a flexion deformity of the finger(s) at the proximal interphalangeal joint (1906).