Coordinates: 51°30′14″N 0°07′34″E / 51.504°N 0.1261°E / 51.504; 0.1261

Thamesmead is a district of south-east London, England, located in the London Boroughs of Greenwich and Bexley. It is situated 9.4 miles (15.1 km) east of Charing Cross.

Thamesmead is the name given to a group of disparate mainly social housing developments built from the late 1960s onwards mostly on former marshland on the southern banks of the River Thames, between the established towns of Woolwich and Belvedere. Originally planned to have 60,000-100,000 residents, it is now estimated to be on target for a final population of around 50,000 people.

Most of the land area of Thamesmead previously formed about 1,000 acres (4.0 km²) of the old Royal Arsenal site that extended over Plumstead Marshes and Erith Marshes. There is some evidence of prehistoric human occupation of the area - flints, animal bone and charcoal were found in bore holes around Western and Central Way in 1997 by the Museum of London Archaeological Service (MOLAS). In Roman times, the river level was significantly lower, and work by MOLAS in 1997 around Summerton Way found evidence of field ditches and pottery and quernstones from Germany dating from around the 3rd or 4th century. After the Roman era, river levels rose again and the area reverted to marshland. According to Hasted, some areas of this marshland were drained by 1279 by the monks of Lesnes Abbey.