Duiliu Marcu (1885, Calafat - 9 March 1966, Bucharest) was a Romanian architect. He studied at the Bucharest Superior School of Architecture and the École nationale supérieure des Beaux-Arts in Paris where he graduated in 1912.
His early designs were for houses and at first followed the French classical style, typical for the period.
By the early 1920s he was practicing in a stylised version of the Neo-Romanian, that became increasingly refined. The facade of the Timisoara Theatre is one of the outstanding examples of what had become his personal style.
By the early 30s, along with most Romanian architects, his work was heavily influenced by the modern movement, but often combined with traditional or classical influences. He produced a number of simple cubic villas with a single arched doorway or rustic details, but also some simple streamlined apartment houses. The House of State Monopolies in Bucharest is his most daringly modern design. 
He is best known for designing some of the largest government building projects in Bucharest in the 1930s, employing stylised classical forms influenced by Italian rationalist architecture of the period. They include the Military Academy, the Victoria Palace and the CFR (State Railways) Palace.
A full list of his projects can be found at the META page for Diuliu Marcu.
- Polytechnic of Timisoara, 1920-1923
- Theater of Timisoara, 1923-1928
- Union Square, Oradea, (layout, lamps, fences), 1926
- Elisabeth Palace, 1930-1937
- CFR Palace, 1934-1937
- Palace of State Monopolies, 1934-1941
- Athenee Palace Hotel, 1935-1937 (renovation alteration of the facades)
- Military Academy building, 1937-1939
- Victoria Palace, 1937-1944-1952
Media related to Duiliu Marcu at Wikimedia Commons