Jan Zachwatowicz (March 4, 1900 – August 18, 1983) was a Polish architect, architectural historian, and restorer.
Zachwatowicz was born in Gatchina. He studied Industrial Civil Engineering at the Saint Petersburg Polytechnical University, and graduated from the School of Architecture at the Warsaw University of Technology in 1930. He was awarded with the Honorary Award by SARP (1971; Polish: Honorowa Nagroda Stowarzyszenie Architektów Polskich).
He was a professor of the Warsaw University of Technology (since 1946; he worked there since 1925), member of the Polish Academy of Sciences (since 1952), member of the Académie d'architecture in Paris (since 1967), member of the International Council on Monuments and Sites, general restorer of relics in Poland (from 1945 to 1957; Polish: Generalny Konserwator Zabytków), chairman of the Architectural-Restoration Committee (since 1971; Polish: Komisja Architektoniczno-Konserwatorska), and chairman of the Civil Committee of Royal Castle in Warsaw Reconstruction (Polish: Obywatelski Komitet Odbudowy Zamku Królewskiego w Warszawie).
Zachwatowicz contributed to reorganization and enlargement of Polish restoration service. During the occupation of Poland (1939–1945) he took a part of teaching, protecting and saving works, i.e. set of relic buildings measurements (including The Market Square of Warsaw Old Town). From January 1945 he co-directed the Warsaw Reconstruction Office (Polish: Biuro Odbudowy Stolicy; f. Biuro Organizacji Odbudowy Warszawy).