Theodor Gustav Pauli (usually Gustav Pauli) (2 February 1866, Bremen - 8 July 1938, Munich) was a German art historian and museum director in Bremen and Hamburg.
Gustav Pauli was the son of Bremen city senator and mayor, Alfred Pauli (1827-1915). He studied art history in Strasbourg, and then in Leipzig under Anton Heinrich Springer. Pauli wrote his thesis on the Renaissance in Bremen and graduated in Leipzig in 1889. He worked as a research assistant in the Kupferstichkabinett, Dresden alongside Max Lehrs from 1889 until 1891. When Springer died in 1891, Pauli applied to study under Jacob Burckhardt in Basel. Burckhardt, upon discovering that Pauli had spent time with the prickly Springer, declared that Springer's former students were "unteachable", but accepted him anyway.
In the summer of 1899, Pauli was appointed to the Kunsthalle Bremen. He engaged the gallery with modern German art, including the first monographic (and sadly, posthumous) exhibition of work by Paula Modersohn-Becker in 1908. He also collected a large number of German and French Impressionist works, which today form the core of the Kunsthalle's collection. In 1911, his purchase of Vincent van Gogh's Poppy Field caused a protest, led by Carl Vinnen, a German painter from Worpswede. Pauli's preference for modern works was seen by some, such as the painter, poet and critic Arthur Fitger, as both dissolute and irrelevant. Like his contemporary gallerist Hugo von Tschudi, Pauli collected works of modern painting at a time when it was deeply unattractive to the broader public, and unappreciated by many art critics.