Dalgety Bay (/dælˈɡɛti ˈbeɪ/ ) is a coastal town and parish in Fife, Scotland, on the north shore of the Firth of Forth, 9 miles from Edinburgh city centre. The civil parish is the 8th largest in Fife with a population of 10,777 (2011)

Dalgety bay was named after the original village of Dalgety, evident by the ruins of the 12th century St Bridget's Kirk. The root of the place-name Dalgety is the Scottish Gaelic word dealg, 'thorn', and the full name originally meant 'the place of the thorn[-bushes]'. The new town, of which building started in 1965, takes its name from the main bay it adjoins, but the town stretches over many bays and coves including Donibristle Bay and St David's Bay.

Dalgety Bay is a commuter town and around 30% of the towns' workers work in Edinburgh. While the architecture of the town reflects construction by volume housebuilders, the town is a regular winner of the Best Kept Small Town title. Dalgety Bay contains 9 Listed Buildings or structures by Historic Scotland, and features on the Fife Coastal Path.

Dalgety Bay began as the village of Dalgety, which was built on the site of the 12th century St Bridget's Kirk.The land surrounding the town was part of the estate owned by the Earls of Moray who built Donibristle House as their residence. In 1592 James Stewart, 2nd Earl of Moray was murdered on the seashore near Donibristle by his rival George Gordon, Earl of Huntly, which is remembered in the popular ballad The Bonnie Earl O' Moray.

Towards the end of the 18th century, the village was destroyed by order of the Earls of Moray. and the inhabitants dispersed. During the First World War Morton Gray Stuart, 17th Earl of Moray donated a portion of his land to the Crown, which built an airfield there in 1917 as a base for the Royal Naval Air Service. The town also sent 30 men into the First World War, with only eight returning unharmed. The Royal Naval Air Service improved and expanded the aerodrome during the Second World War as HMS Merlin, an air station, and constructed an extensive aircraft maintenance facility there.

Construction of the modern town of Dalgety Bay as Scotland's first "enterprise town" began around 1965 on the site of RNAS Donibristle and much of the remaining ground of the Earls of Moray family seat, Donibristle House. The town stretches across several bays and coves of the northern coast of the Firth of Forth including Donibristle Bay and St David's Bay.

There are two primary schools in Dalgety Bay: Dalgety Bay Primary School and Donibristle Primary School. Dalgety Bay sits within the catchment area for Inverkeithing High School.

A series of radioactive objects have been found on the shoreline of Dalgety Bay since the 1990s. The objects come from an eroded landfill that contains debris from Second World War aircraft that originally had radium dials. One found in 2011 measured 10 MBq. Since 1990, more than 2,500 radioactive hotspots have been found on the Dalgety Bay foreshore, one-third of them since September 2011. On 25 April 2012, the Ministry of Defence and the Scottish Environment Protection Agency agreed a joint survey of the problem. As of 2012, the MoD was conducting a 12-month investigation of the contamination to try to avoid Dalgety Bay "becoming the first place in the UK to be legally designated as radioactive contaminated land". In 2013, SEPA found that the MoD was solely responsible for the contamination. In early 2014 the MoD made four proposals regarding how to deal with the contamination, ranging from erecting fences to keep the public out, to sealing it in with concrete.

In September 2023, SEPA announced that the operation to remove the contamination had been successfully completed and that the relevant stretch of shoreline was now safe for public access for the first time since 2011. Some 6,500 radioactive particles, mostly of low activity, had been removed, with a purpose-built scanner being used to detect the particles. The project had previously been reported to cost £10.5 million.

• Ócsa, Hungary

• Dalgety Bay on FifeDirect
• Dalgety Bay and Hillend community website
• A short tour of Dalgety Bay - includes maps and aerial photographs
• Dalgety Bay Weather Station Archived 19 October 2019 at the Wayback Machine
• Fife Place-name Data :: Dalgety
• Fleet Air Arm archive
• Radioactive contamination