Anglo-Saxon architecture was a period in the history of architecture in England from the mid-5th century until the Norman Conquest of 1066. Anglo-Saxon secular buildings in Britain were generally simple, constructed mainly using timber with thatch for roofing. No universally accepted example survives above ground. Generally preferring not to settle within the old Roman cities, the Anglo-Saxons built small towns near their centres of agriculture, at fords in rivers or sited to serve as ports. In each town, a main hall was in the centre, provided with a central hearth.

There are many remains of Anglo-Saxon church architecture. At least fifty churches are of Anglo-Saxon origin with major Anglo-Saxon architectural features, with many more claiming to be, although in some cases the Anglo-Saxon part is small and much-altered. It is often impossible to reliably distinguish between pre- and post-Conquest 11th century work in buildings where most parts are later additions or alterations. The round-tower church and tower-nave church are distinctive Anglo-Saxon types. All surviving churches, except one timber church, are built of stone or brick, and in some cases show evidence of re-used Roman work.

The architectural character of Anglo-Saxon ecclesiastical buildings range from Celtic influenced architecture in the early period; Early Christian basilica influenced architecture; and in the later Anglo-Saxon period, an architecture characterised by pilaster-strips, blank arcading, baluster shafts and triangular headed openings. In the last decades of the Anglo-Saxon kingdoms, a more general Romanesque style was introduced from the continent, as in the now built-over additions to Westminster Abbey made from 1050 onwards, already influenced by Norman style. In recent decades, architectural historians have become less confident that all undocumented minor "Romanesque" features post-date the Norman Conquest. Although once common, it has been incorrect for several decades to use the plain term "Saxon" for anything Anglo-Saxon that is later than the initial period of settlement in Britain.

Anglo-Saxon secular buildings were normally rectangular post-built structures, where timber posts were driven into the ground to form the framework of the walls upon which the thatched roofs were constructed. Only ten of the hundreds of settlement sites that have been excavated in England from this period have revealed masonry domestic structures and confined to a few quite specific contexts. The usual explanation for the tendency of Anglo–Saxons to build in timber is one of technological inferiority or incompetence. However it is now accepted that technology and materials were part of conscious choices indivisible from their social meaning. Le Goff suggests that the Anglo-Saxon period was defined by its use of wood, providing evidence for the care and craftsmanship that the Anglo–Saxon invested into their wooden material culture, from cups to halls, and the concern for trees and timber in Anglo–Saxon place–names, literature and religion. Michael Shapland suggests:

The stone buildings imposed on England by the Romans would have been 'startling' and 'exceptional', and following the collapse of Roman society in the fifth century there was a widespread return to timber building, a 'cultural shift' that it is not possible to explain by recourse to technological determinism.

Anglo–Saxon building forms were very much part of this general building tradition. Timber was 'the natural building medium of the age': the very Anglo–Saxon word for 'building' is 'timbe'. Unlike in the Carolingian world, late Anglo–Saxon royal halls continued to be of timber in the manner of Yeavering centuries before, even though the king could clearly have mustered the resources to build in stone. Their preference must have been a conscious choice, perhaps an expression of 'deeply–embedded Germanic identity' on the part of the Anglo–Saxon royalty.

Though very little contemporary evidence survives, methods of construction, including examples of later buildings, can be compared with methods on the continent. The major rural buildings were sunken-floor (Grubenhäuser) or post-hole buildings, although Helena Hamerow suggest this distinction is less clear. An excavated example is at Mucking in Essex. In addition to the sunken huts, vernacular buildings from the migration period found at Mucking included more substantial halls up to 50 feet (15 m) long and 25 feet (7.6 m) wide with entrances in the middle of both longer sides.

Even the elite had simple buildings, with a central fire and a hole in the roof to let the smoke escape and the largest of which rarely had more than one floor, and one room. Buildings vary widely in size, most were square or rectangular, though some round houses have been found. Frequently these buildings have sunken floors; a shallow pit over which a plank floor was suspended. The pit may have been used for storage, but more likely was filled with straw for winter insulation. A variation on the sunken floor design is found in towns, where the "basement" may be as deep as nine feet, suggesting a storage or work area below a suspended floor. Another common design was simple post framing, with heavy posts set directly into the ground, supporting the roof. The space between the posts was filled in with wattle and daub, or occasionally, planks. The floors were generally packed earth, though planks were sometimes used. Roofing materials varied, with thatch being the most common, though turf and even wooden shingles were also used.