Paul Engelmann (14 June 1891 – 5 February 1965) was a Viennesearchitect who is now best known for his friendship with the philosopher Ludwig Wittgenstein between 1916 and 1928, and for being Wittgenstein's partner in the design and building of the Stonborough House in Vienna.
Engelmann was born at Olmütz in 1891, and studied with the modernist architect Adolf Loos in Vienna. He was supposedly Loos's favourite pupil. He was private secretary to Karl Kraus. He lived mainly in Vienna and Olomouc before he emigrated to Palestine in 1934 and settled in Tel Aviv, where he died in 1965.
In November 1925, Wittgenstein’s sister Margaret Stonborough-Wittgenstein commissioned Engelmann, to design and build a large town house in Vienna in the Kundmanngasse. Wittgenstein showed a great interest in the project and in Engelmann’s plans. He convinced Engelmann that he could realise his sister’s intentions much better, and was eventually asked to be the architect of the house.