The Guest family is a British family that has been prominent in business and politics since the 18th century. It was involved in the British iron and steel industry, particularly the Dowlais Ironworks in Wales, which later became part of Guest, Keen and Nettlefolds. Hereditary titles held by members of the family include Baron Wimborne, Baron Ashby St Ledgers, and Viscount Wimborne, all in the Peerage of the United Kingdom.

The Dowlais Ironworks was a major ironworks and steelworks located at Dowlais near Merthyr Tydfil, in Wales. Founded in the 18th century, it operated until the end of the 20th, at one time in the 19th century being the largest steel producer in the UK. Dowlais Ironworks were the first business to license the Bessemer process, using it to produce steel in 1865. Dowlais Ironworks was one of the four principal ironworks in Merthyr. The other three were Cyfarthfa, Plymouth, and Penydarren Ironworks. In 1936 Dowlais played a part in the events leading to the abdication crisis of Edward VIII, when the King visited the steelworks and was reported as saying that "these works brought these men here. Something must be done to get them back to work", a statement which was seen as political interference. The steelworks closed in 1987.