Regency architecture encompasses classical buildings built in the United Kingdom during the Regency era in the early 19th century when George IV was Prince Regent, and also to earlier and later buildings following the same style. The period coincides with the Biedermeier style in the German-speaking lands, Federal style in the United States and the French Empire style. Regency style is also applied to interior design and decorative arts of the period, typified by elegant furniture and vertically striped wallpaper, and to styles of clothing; for men, as typified by the dandy Beau Brummell and for women the Empire silhouette.

The Regency era of British history is commonly described as the years between c. 1795 and 1837, although the official regency for which it is named only spanned the years 1811 to 1820. King George III first suffered debilitating illness in the late 1780s, and relapsed into his final mental illness in 1810; by the Regency Act 1811, his eldest son George, Prince of Wales, was appointed prince regent to discharge royal functions. When George III died in 1820, the Prince Regent succeeded him as George IV. In terms of periodisation, the longer timespan is roughly the final third of the Georgian era (1714–1837), encompassing the last 25 years or so of George III's reign, including the official Regency, and the complete reigns of both George IV and his brother and successor William IV. It ends with the accession of Queen Victoria in June 1837 and is followed by the Victorian era (1837–1901).