Dirleton Castle is a medieval fortress in the village of Dirleton, East Lothian, Scotland. It lies around 2 miles (3.2 km) west of North Berwick, and around 19 miles (31 km) east of Edinburgh. The oldest parts of the castle date to the 13th century, and it was abandoned by the end of the 17th century.

Begun in around 1240 by John De Vaux, the castle was heavily damaged during the Wars of Scottish Independence, when it was twice taken by the English. In the 14th century, Dirleton was repaired by the Haliburton family, and it was acquired by the Ruthvens in 1505. The Ruthvens were involved in several plots against Mary, Queen of Scots, and King James VI, and eventually forfeited the castle in 1600. Dirleton ceased to be a residence, although Oliver Cromwell was forced to besiege the castle to flush out a band of "mosstroopers" (marauders), during the Third English Civil War in 1650. The damaged castle was then acquired by John Nisbet, Lord Dirleton, who decided to build a new country house on the nearby Archerfield Estate. The Nisbet family of Dirleton continued to maintain the castle's gardens, before handing Dirleton into state care in 1923. The ruins and gardens are now maintained by Historic Environment Scotland.

Dirleton Castle stands on a rocky outcrop, at the heart of the rich agricultural lands of the barony of Dirleton, and guards the coastal approach to Edinburgh from England, via the port of North Berwick. The ruins comprise a 13th-century keep, and a 16th-century house which the Ruthvens built adjacent. Only the basement levels survive of the 14th- and 15th-century additions built by the Haliburtons, although these comprised a large hall and tower house along the east range. Other buildings within the courtyard have also been demolished. Surrounding the castle are gardens, which may have been first laid out in the 16th century, although the present planting is largely of the 20th century. The garden walls enclose a 16th-century doocot, or pigeon house.

The Norman family of de Vaux originated in Rouen, northern France, and settled in England following the Norman Conquest of 1066. Two de Vaux brothers, or cousins, were among a number of Anglo-Norman knights invited to Scotland, and granted land, by King David I of Scotland in the 12th century. Hubert de Vaux was given the barony of Gilsland in Cumbria, at that time part of Scotland, while John de Vaux was granted the barony of Dirleton. John built a castle at Eldbotle, probably to the north-west of modern Dirleton, and another, named Tarbet Castle, on the island of Fidra, although neither survives.

In 1220, Fidra was gifted to the monks of Dryburgh Abbey by William de Vaux. William's son, another John, had been held hostage in England as surety for the good conduct of King William the Lion in 1213, and succeeded to the barony in the 1220s. He then began the construction of a replacement for Tarbet at Dirleton, which was recorded as a "castellum" in 1225, although this may refer to an earlier timber structure. In 1239, de Vaux was appointed seneschal, or steward, to Marie de Coucy, on her marriage to King Alexander II. Marie de Coucy was the daughter of Enguerrand III, Lord of Coucy (d.1242), builder of the Château de Coucy, in Picardy (c.1220s), which probably served as a model for Dirleton. The 13th-century stone castle, of which only the donjon, or keep, remains, represented a show of de Vaux's status, and would have required peaceful times to permit a prolonged construction project.

Peaceful times ended in 1296, with the outbreak of the Wars of Scottish Independence. Dirleton, which guarded the route between Edinburgh and the English border, changed hands several times through the invasions of the English under King Edward I. During the campaign of summer 1298, the castle was besieged by English forces under Antony Bek, the Bishop of Durham. Dirleton withstood the assault for several months, until the English victory at Falkirk allowed them to bring up large siege engines, after which the castle was soon reduced. Dirleton was garrisoned by the English, but must have been retaken by the Scots before 1306, when the English commander Aymer de Valence, 2nd Earl of Pembroke recaptured Dirleton once more. It was finally retaken by the Scots some time before 1314, and was slighted, or deliberately damaged, to prevent its reuse by the English.

The castle and lands of Dirleton passed to the Berwickshire family of Haliburton (or Halyburton) when John Haliburton (d.1355) married the heiress of the de Vaux family, shortly before 1350. The castle had been repaired by 1363, when it was seized by William Douglas, 1st Earl of Douglas, during his brief rebellion against King David II, although it was later returned to the Haliburtons. In the 1420s, Sir Walter Haliburton (d. before 1447) acted as a hostage in exchange for the release of King James I, who had been held captive by the English since 1406. He was rewarded in 1439 by being appointed Treasurer of Scotland. Either Walter, or his eldest son John (d. before 1454), was ennobled as a Lord of Parliament in the 1440s, with the title Lord Dirletoun. The Haliburtons carried out extensive works at Dirleton, heightening the original towers, and constructing a new gatehouse to the south-east. A large hall and tower house were added to the castle in the 15th century, forming the east range.

King James IV visited Dirleton in September 1505, and gave money to the masons then engaged on works in the north-east part of the castle. Later that year, Patrick, the last Haliburton of Dirleton, died, and his estates were divided among his three daughters, Janet, Margaret, and Mariotta. James IV made Patrick Haliburton's widow Christiane Wawane and her brother William Wawane keepers of Dirleton in August 1507.