Beecroft Art Gallery is an English art gallery in the town of Southen-on-sea. It is part of the Southend Museums. The gallery has a permanent collection, started in the 1970s, of over 2000 works. The collection, in particular, hosts a good representation of Dutch paintings and in addition to them also artists such as Molenaer, Ruisdael, Berchem, Rossetti, Constable, Edward Lear, Carel, Jacob Epstein and Alan Sorrell, a local artist from Essex. Also housed here is the Thorpe Smith Collection which includes views of local landscapes depicted on paintings, drawings and prints since 1803.

The Beecroft Art Gallery stands out in particular for exhibiting masterpieces from the decades from the 1920s to the 1970s, along with important pieces from previous years, most notably a rare 17th-century slap-soled shoe. Not surprisingly, beachwear is one of the main collection areas: in 2009 Southend received a donation of 500 swimwear from the private collector, Mavis Plume. They date from around 1900 to the 1980s and include several rare pieces.