Architecture in modern Scotland encompasses all building in Scotland, between the beginning of the twentieth century and the present day. The most significant architect of the early twentieth century was Charles Rennie Mackintosh, who mixed elements of traditional Scottish architecture with contemporary movements. Estate house design declined in importance in the twentieth century. In the early decades of the century, traditional materials began to give way to cheaper modern ones. After the First World War, Modernism and the office block began to dominate building in the major cities and attempts began to improve the quality of urban housing for the poor, resulted in a massive programme of council house building. The Neo-Gothic style continued in to the twentieth century but the most common forms in this period were plain and massive Neo-Romanesque buildings.

After the Second World War, brutalist tower blocks were adopted as a solution and this period saw the building of new towns, including Glenrothes and Cumbernauld, but the social and building problems of these constructions soon became apparent. The creation of new towns and council house estates necessitated the rapid supply of new churches. From the 1980s Scottish architecture began to recover its reputation, with new buildings like that created to house the Burrell Collection in Glasgow and more recently the Scottish Parliament Building in Edinburgh. There has also been urban regeneration, involving the replacement and renovation of existing buildings and landscapes. The 1980s saw the growth of speculative house building by developers and the introduction of English brick and half-timbered vernacular styles to Scotland. As the production of state sponsored housing subsided in the 1970s there was a return to conservatism in church design, but there were some original and post-modern designs from the 1980s.

Glasgow style and the early twentieth century

The most significant Scottish architect of the early twentieth century, having a considerable influence on European architecture, was Charles Rennie Mackintosh (1868–1928). He mixed elements of the Scottish baronial architecture, Arts and Crafts Movement and the Art Nouveau to produce elegant modern buildings. His major work included The Willow Tearooms in Sauchiehall Street, Glasgow (1903), Glasgow School of Art (1897–1909) and Hill House, Helensburgh (1902–04).A. L. Palmer, The A to Z of Architecture (Scarecrow Press, 2009), , p. 34. The influence of Mackintosh's Glasgow style can be seen in the work of architects like James Salmon (1873–1924), whose designs included the heavily glass-fronted, Art Nouveau "Hatrack" (1899–1902) on Vincent Street and the Lion Chambers, Hope Street (1904–05), an early example of reinforced concrete construction.M. Glendinning, R. MacInnes and A. MacKechnie, A History of Scottish Architecture: from the Renaissance to the Present Day (Edinburgh: Edinburgh University Press, 2002), , p. 368.

Estate house design declined in importance in the twentieth century. An exception was the work undertaken by John Kinross (1855–1955). Beginning with the reconstruction of Thurston House, Dunbar, from 1890, he undertook a series of major country house designs."John Kinross", Dictionary of Scottish Architect, retrieved 9 February 2012. The most important was Manderston House (1901–03), built for James Miller in the Adam style.H. Montgomery-Massingberd and C. S. Sykes, Great Houses of Scotland (Laurence King Publishing, 1997), , p. 9. Skibo Castle was rebuilt for industrialist Andrew Carnegie (1899–1903) by Ross and Macbeth. English architect C. H. B. Quennell designed a neo-Georgian mansion at Altmore (1912–14) for the owner of a Moscow department store. There was a lull in building after the First World War and social change undermined the construction of rural country houses.D. Mays, "Country seat 1600–Present", in M. Lynch, ed., Oxford Companion to Scottish History (Oxford: Oxford University Press, 2011), , pp. 326–8.

In the twentieth century the distinctive Scottish use of stone architecture declined as it was replaced by cheaper alternatives such as Portland cement, concrete, and mass-production brick. Stone would however be retained as a material for some housing stock in Edinburgh, Aberdeen and Dumfries, and would undergo revivals.I. Maxwell, "A History of Scotland's Masonry Construction" in P. Wilson, ed., Building with Scottish Stone (Edinburgh: Arcamedia, 2005), , p. 29. In the twentieth century private architecture was increasingly client driven. James Robert Rhind (1854–1918), the son of David Rhind, was successful in the competition for new libraries to be constructed in Glasgow following Andrew Carnegie's gift of £100,000 to the city in 1901. His designs were selected for seven libraries, allowing him to demonstrate his individual interpretation of Edwardian Baroque architecture. Rhind's libraries were all built with locally quarried sandstone, which blended in with the existing tenement neighbourhoods. His landmark buildings were greatly enhanced by his liberal use of columns, domes and sculpted features."Baroque libraries in Glasgow" , Carnegie Libraries of Scotland, retrieved 11 May 2012. James Miller (1860–1947) is noted for his Scottish railway stations, such as his 1901–05 extensions to Glasgow Central railway station,E. Williamson, A. Riches and M. Higgs, Glasgow (New Haven, CT: Yale University Press, 1990), , p. 97. and the spectacular Wemyss Bay railway station on the Firth of Clyde.F. A. Walker, The South Clyde Estuary: An Illustrated Architectural Guide to Inverclyde and Renfrew (Edinburgh: Royal Incorporation of Architects in Scotland, 2006), , p. 146.

Early modernism

After the First World War, Miller and his chief designer Richard Gunn (1889–1933) along with others, adapted to the growing needs of the office block. In Glasgow, with its central gridiron plan, this followed the practice in the United States of filling up entire blocks and building steel framed buildings as high as the fire marshal would allow, as in the heavily American-influenced Union Bank building (1924) at St Vincent Street.M. Glendinning, R. MacInnes and A. MacKechnie, A History of Scottish Architecture: from the Renaissance to the Present Day (Edinburgh: Edinburgh University Press, 2002), , p. 395. From the mid-twentieth century, public architecture became more utilitarian, as part of the impulse to produce a comprehensive welfare state. Thomas S. Tait (1882–1954) was among the most important modernist architects of the era, using pyramidal stepped designs for buildings like the St Andrew's House, Edinburgh (1935–39) built for the Scottish Office, and the 1939 "Tower of Empire" for the Empire Exhibition, Scotland 1938, held in Bellahouston Park, Glasgow.M. Gardiner, Modern Scottish Culture (Edinburgh: Edinburgh University Press, 2005), , p. 173. There was a lull in building after the First World War and social change undermined the construction of rural country houses. Isolated examples included the houses that combined modern and traditional elements, designed by Basil Spence and built at Broughton Place (1936) and Gribloch (1937–9). After World War Two a shortage of building materials further reduced the number of large luxury houses. Isolated examples included Logan House, designed by David Style in the 1950s. In the 1960s there was Basil Hughes's design at Snaigow for Earl Cadogan and the remodelling of Gask House by Claude Phillimore. This period also saw considerable restoration of existing houses.

During the First World War the government became increasingly aware of Scotland's housing problems, particularly after the Glasgow rent strike of 1915. A royal commission of 1917 reported on the "unspeakably filthy privy-middens in many of the mining areas, badly constructed incurably damp labourers' cottages on farms, whole townships unfit for human occupation in the crofting counties and islands ... groups of lightless and unventilated houses in the older burghs, clotted masses of slums in the great cities".A. McIntosh Gray and W. Moffat, A History of Scotland: Modern Times (Oxford: Oxford University Press, 1999), , pp. 70–1. The result was a massive programme of council house building. Many early council houses were built on greenfield sites away from the pollution of the city, often constructed of semi-detached homes or terraced cottages. Knightswood, north-west of Glasgow, was built as a show piece from 1923 to 1929, with a library, social centre and seven shopping "parades". In the 1930s schemes tended to be more cheaply built, like Blackhill, Glasgow, with a thousand houses built as two and three story tenements. These building schemes were designed to rehouse those displaced by urban slum clearance, by which thousands of tenements were demolished. However, often crammed into poor land near railways or gasworks, they soon became notorious. A survey of 1936 found that almost half of Scotland's houses were still inadequate.

The Neo-Gothic style that had become almost universal for church building in the late nineteenth century continued in to the twentieth, with examples including L. G. Thomson's Reid Memorial Church, Edinburgh (1929–33). However, the most common forms in this period were plain and massive Neo-Romanesque buildings. Protestant examples included H. O. Tarbolton's Bangour Village Church (1924–30) and Roman Catholic examples included Reginald Fairlie's Immaculate Conception Church, Fort William (1933–34).M. Glendinning, R. MacInnes and A. MacKechnie, A History of Scottish Architecture: From the Renaissance to the Present Day (Edinburgh: Edinburgh University Press, 1996), , p. 418. The reunification of the Church of Scotland in 1929 removed much of the need for new Presbyterian church-building, which was replaced by a tendency towards renovating nineteenth-century churches. The main tendency in church design in the 1930s was a move towards classicism. There were isolated large classical Protestant commissions, such as Bristo Baptist Church, Edinburgh (1933–35), but the major buildings in this form were in the Catholic Church where there was a movement towards worshipper-centred basilican plans, after the pontificate of Pius X (1903–14). This movement reached its peak in the 1960s after the Second Vatican Council. The leading figure in pursuing this style was Giacomo Antonio (Jack) Coia of Gillespie, Kidd & Coia. From the later 1920s he pursued a brick style of Catholic architecture. Coia's first church, St Anne's, Dennistoun (1931), utilised the engineering techniques of Beaux-Arts architecture, resulting in a broad, centralised space, with narrow arcades rather than aisles, with a monumental facade of red-brick. He used a more linear plan in subsequent designs, including St Patrick, Greenock (1934–35). Coia's partner T. Warnett Kennedy's temporary, open-roofed Catholic chapel at the Empire Exhibition (1938) was fronted by a Mackintosh-like grid of metalwork, and with his St Peter in Chains Church, Ardrossan (1938), with austere walls and towers, showed the influence of the "abstract compositions" of contemporary Swedish architecture and pointed to the future influence of modernism.M. Glendinning, R. MacInnes and A. MacKechnie, A History of Scottish Architecture: From the Renaissance to the Present Day (Edinburgh: Edinburgh University Press, 1996), , p. 417.

Post-war brutalism