The year 1756 in architecture involved some significant events.

• Greek Revival architecture appears in the window design for Nuneham House in Oxfordshire, England, by Stiff Leadbetter.^[1]
• John Smeaton produces the first high-quality cement using hydraulic lime since Roman times for construction of the third Eddystone Lighthouse (completed 1759).

• Replacement Catherine Palace, Tsarskoye Selo in Russia, designed by Francesco Bartolomeo Rastrelli, is completed.
• Klov Palace, Kiev in Russia, probably designed by Gottfried Schädel and Pyotr Neyelov, is completed.
• Replacement Basilica of the Birth of the Virgin Mary, Chełm in Poland, designed by Paweł Fontana, is completed.
• Reconstruction of Abbot's Palace (Oliwa) in Gdańsk, Poland, is completed.
• Newbridge, now Old Bridge, Pontypridd in Wales, designed by William Edwards, is completed.^[2]
• St Andrew's in the Square, Glasgow, Scotland, designed by Allan Dreghorn, is completed.^[3]
• Octagon Chapel, Norwich in England, designed by Thomas Ivory, is completed.^[4]
• Original Whitefield's Tabernacle, Tottenham Court Road in London is built.
• Trafford Hall in England is built.
• Wrotham Park, Hertfordshire in England, designed by Isaac Ware, is completed.
• Shaw Mansion (New London, Connecticut) is built.
• The President's House (Princeton), New Jersey, is built.
• First Presbyterian Church (Newburyport, Massachusetts) is built.
• Alloways Creek Friends Meetinghouse, Hancock's Bridge, New Jersey, is built.
• Saint Gevorg of Mughni Church, Tbilisi in Armenia is completely rebuilt.
• St John the Evangelist Church, Shobdon, Herefordshire, England, is completely rebuilt with a "Strawberry Hill Gothic" interior.^[5] Elements of the previous building are incorporated in folly arches nearby.

• Isaac Ware publishes A Complete Body of Architecture in London.

• February 29 – C. F. Hansen, Danish architect (d. 1845)
• Chrystian Piotr Aigner, Polish architect (d. 1841)
• Giovanni Antonio Antolini, Italian architect (d. 1841)
• 1756 or 1758 – Francesco Piranesi, Italian-born architectural engraver and architect (d. 1810)

• July 1 – Giambattista Nolli, Italian architect and surveyor (b. 1701)