The year 1808 in architecture involved some significant events.

• Arc de Triomphe du Carrousel, Paris, France.
• Fort Edgecomb, an octagonal, wooden, two-story blockhouse, built in Lincoln County, Maine, USA, to protect Wiscasset's seaport (settled in 1663 on the tidal waters of the Sheepscot River).
• Fountain in front of Mission Santa Barbara, California, USA.
• Hotel Polski, Warsaw, Poland.
• Potseluev Bridge (new cast-iron bridge) across the Moyka River in Saint Petersburg, Russia.
• Sheffield Old Town Hall, England, UK.
• Leeds Library, England, UK, by Thomas Johnson.
• Sparks Shot Tower in Philadelphia, Pennsylvania, USA.
• Teatro della Concordia, designed by Luigi Canonica, in Cremona, Italy.
• Reconstruction of palace at Natolin, Poland, by Chrystian Piotr Aigner for Stanisław Kostka Potocki.

• Grand Prix de Rome, architecture: Achille-François-René Leclère.

• January 22 – James Fergusson, Scottish writer on architecture (died 1886)
• July 25 – Francis Thompson, English architect working chiefly on railways (died 1895)

• February 13 – Robert Russell, Australian architect and surveyor (died 1900)
• October 28 – Emilio De Fabris, Florentine architect (died 1883)
• date unknown – Jean-Baptiste Schacre, French draughtsman and architect (died 1876)

• February 18 – Giuseppe Piermarini, Italian architect (born 1734)
• March 9 – Joseph Bonomi the Elder, Italian-born architect and draughtsman (born 1739)
• October 1 – Carl Gotthard Langhans, Prussian builder and architect (born 1732)