The year 1940 in architecture involved some significant architectural events and new buildings.

Events

• Oscar Niemeyer begins to design landmark public buildings around the artificial lake of Pampulha in Belo Horizonte, state of Minas Gerais in southeastern Brazil.
• The last of the White Pine Series of Architectural Monographs, begun in 1916, is published.
• Thomas Sharp's Pelican book Town Planning is published in the United Kingdom.
• November 9 – Major fire at Castle Howard in England.^[1]

Buildings and structures

Buildings completed

• Igreja Nossa Senhora do Brasil in São Paulo, Brazil.^[2]
• St. Mark's Church, Belgrade, Serbia.
• Church of St. Michael, Črna Vas, Slovenia, designed by Jože Plečnik.
• Timișoara Orthodox Cathedral, Timișoara, Romania.
• Grundtvig's Church, Bispebjerg, Copenhagen, Denmark, designed by Peder Vilhelm Jensen-Klint (d.1930) in 1913 and completed by his son Kaare Klint.
• Church and Priory of Christ the King, Cockfosters, London, designed by Dom Constantine Bosschaerts.
• Raleigh Hotel in Miami Beach, Florida, United States, designed by Lawrence Murray Dixon.
• Replacement Llao Llao Hotel at San Carlos de Bariloche, Argentina, designed by Alejandro Bustillo.
• Civic Centre of San Carlos de Bariloche, Argentina, designed by Ernesto de Estrada.
• New Bodleian Library in the University of Oxford, England, designed by Sir Giles Gilbert Scott.
• Atatürk Bridge, Istanbul, Turkey (the fourth bridge on this site).^[3]
• Eastern Michigan Motorbus Terminal in Ann Arbor, United States, designed by Banfield and Cumming with Douglas Loree.
• Detroit Arsenal (Warren, Michigan) Tank Plant, designed by Albert Kahn.
• Walton Yacht Works at Walton on Thames, England, designed by Jane Drew.
• No. 4 Boathouse at HMNB Portsmouth, England, designed by E. A. Scott.

Awards

• American Academy of Arts and Letters Gold Medal – William Adams Delano.
• RIBA Royal Gold Medal – Charles Voysey.

Births

• January 14 – Helmut Jahn, German-American architect
• March 26 – Jörg Streli, Austrian architect and academic (died 2019)
• May 31 – Lebbeus Woods, American architect and artist (died 2012)^[4]
• June 24 – Claude Vasconi, French architect (died 2009)
• September 3 – Frank Duffy, British architect

Deaths

• February 27 – Peter Behrens, German architect and designer (born 1868)
• March 24 – Thomas Adams, British urban planner (born 1871)
• June 11
  • Alfred S. Alschuler, Chicago architect (born 1876)
  • John A. Pearson, Canadian architect (born 1867)
• August 22 – Paul Gösch, German artist, architect, lithographer and designer (born 1885)
• October 20 – Gunnar Asplund, Swedish Nordic Classicist architect (born 1885)
• December 13 – Marc Camoletti, Swiss architect (born 1857)