Petre Antonescu (June 29, 1873–April 22, 1965) was a Romanian architect. Over the course of a career that spanned the first half of the 20th century, he established himself as a leader in the field within his country, helping define a national style of neo-Romanian architecture.
Born in Râmnicu Sărat, he completed high school in Bucharest and entered the law faculty of Bucharest University. While there, he became close to important artists who were then grappling with the problem of how to define a specific Romanian art. By 1893, his new passion led Antonescu to abandon law and head to Paris to study architecture. In 1899, he obtained a degree in the field from the École des Beaux-Arts. He obtained six medals while a student and drafted the plan for a Romanian pavilion at the 1900 Exposition Universelle.
In 1900, Antonescu was made honorific professor at Bucharest's School of Architecture, rising to full professor in 1903. He taught the history of architecture from 1900 to 1938, and was the school's rector from 1931 to 1938. According to a former student, he drew beautifully and spoke in short, clear, carefully chosen phrases. Antonescu was active in the realm of conserving and restoring historic monuments, participating in numerous projects during the interwar period. Together with Gheorghe Balș and Nicolae Ghica-Budești, he formed part of the historic monuments committee, helping create a scientific template for restorations.
In 1912 and again from 1919 to 1921, Antonescu was president of the Romanian Architects' Society; he also led the Society of Professional Architects from 1926 to 1932. Elected an honorary member of the Romanian Academy in 1936, he was raised to titular status in 1945. In 1948, the new communist regime stripped him of Academy membership. He was granted the State Prize in 1952 for rebuilding and expanding the Bucharest City Hall, and in 1958 was awarded the Order of the Star of the Romanian Socialist Republic, first class. In 1927, he was made a corresponding member of the Accademia di San Luca in Rome.