Loch Doon

Infobox lake
lake_name = Loch Doon
image_lake = Loch Doon.jpg
caption_lake =
image_bathymetry =
caption_bathymetry =
location = Carrick, Scotland
coords = coord|55.250|N|4.372|W|region:GB_type:waterbody|display=inline,title
type = loch
inflow =
outflow = River Doon
catchment =
basin_countries = United Kingdom
length =
width =
area =
depth =
max-depth =
volume =
residence_time =
shore =
elevation =
islands =
cities =

Loch Doon (Gaelic "Loch Dhùin," pronounced|ɫ̪ɔxˈɣuːɲ) is a body of water, in Carrick, Scotland. It is the source of the River Doon.

In the 13th century, it was a site of a castle owned by the Earls of Carrick. During the Scottish Wars of Independence it was held by one Gille Brighde, Sir Gilbert de Carrick, a native Carrick nobleman who surrendered it to the English. It was soon recovered by the Scots. In the 15th century, it was frequently in the hands of the Kennedy Clan, although it was briefly in the hands of the Maclellans (backed by William Douglas, 8th Earl of Douglas) after a siege in 1446. The castle was destroyed in the 16th century by King James V as part of a general policy of reducing the power of the barons.

The loch was dammed in the 1930s to provide water for the Galloway hydro-electric power scheme. During its construction, the ruins of the castle were moved from an island in the Loch to the shore to avoid the rising water.