Leonard Marconi (Warsaw, 6 October 1835 – 1 April 1899, Lviv) was a Polish and Austro-Hungarian architect and sculptor. He was active chiefly at Warsaw, then in Galicia, notably at Lwów (now Lviv, Ukraine).
Leonard Marconi was born on 6 October 1835 in Warsaw to a well-known artistic family of Italian origin. He was the son of sculptor Ferrante Marconi, nephew of architect Henryk Marconi, and cousin of Leandro Marconi, a famed architect. He graduated from the Academy of Fine Arts in Warsaw, then the Accademia di San Luca in Rome.
In 1861 he returned to Poland and opened an atelier in Warsaw. Fairly successful as a sculptor, in 1873 he was invited to Lwów (then in Austro-Hungarian Galicia) to become a professor at the Technical Academy (Polish: Akademia Techniczna), predecessor of the Lviv Polytechnic.
He died in Lviv on 1 April 1899 and is interred at Lychakiv Cemetery.