Hull Castle was an artillery fort in Kingston upon Hull in England. Together with two supporting blockhouses, it defended the eastern side of the River Hull, and was constructed by King Henry VIII to protect against attack from France as part of his Device programme in 1542. The castle had two large, curved bastions and a rectangular keep at its centre; the blockhouses to the north and south had three curved bastions supporting guns, and a curtain wall and moat linked the blockhouses and castle. The construction project used material from recently dissolved monasteries, and cost £21,056. The town took over responsibility for these defences in 1553, leading to a long running dispute with the Crown as to whether the civic authorities were fulfilling their responsibilities to maintain them.

During the 16th and 17th centuries, the defences were used to imprison Catholic recusants, who were often held in harsh conditions. The castle and blockhouses saw service during the sieges of the English Civil War in the 1640s, and remained in used during the interregnum. After the restoration of Charles II, the buildings were neglected until the King redeveloped the eastern defences of Hull in 1681, creating a larger fortification called the Citadel. The castle and the South Blockhouse formed part of the new design, although the North Blockhouse was allowed to fall into ruins and finally demolished in 1801. The former buildings remained in use, with various modifications, until the Citadel was demolished in 1864 to allow the construction of new docks. The foundations survived and have been the subject of archaeological investigations.

Hull Castle was built as a consequence of international tensions between England, France and the Holy Roman Empire in the final years of the reign of King Henry VIII. Traditionally the Crown had left coastal defences to local lords and communities, only taking a modest role in building and maintaining fortifications, and while France and the Empire remained in conflict, maritime raids were common but an actual invasion of England seemed unlikely. Modest defences based around simple blockhouses and towers existed in the south-west and along the Sussex coast, with a few more impressive works in the north of England, but in general the fortifications were limited in scale.

In 1533, Henry broke with Pope Paul III over the annulment of his long-standing marriage to Catherine of Aragon. Catherine was the aunt of Charles V, the Holy Roman Emperor, who took the annulment as a personal insult. This resulted in France and the Empire declaring an alliance against Henry in 1538, and the Pope encouraging the two countries to attack England. An invasion of England appeared certain. In response, Henry issued an order, called a "device", in 1539, giving instructions for the "defence of the realm in time of invasion" and the construction of forts along the English coastline. The immediate threat passed, but resurfaced in 1544, with France threatening an invasion across the English Channel, backed by her allies in Scotland. Henry therefore issued another device to further improve the country's defences.

Hull Castle was constructed to defend the east side of the town of Kingston upon Hull against a possible French attack; it was also intended to ensure the loyalty of the population, who had taken part in a revolt against the King in 1536. Henry had visited Hull in late 1541 and had observed that, although the town had strong walls to the north and west, it lacked adequate defences in the event of an attack from the east, while the harbour was only protected by a "little round brick tower". Henry issued orders for the existing town defences to be repaired and renovated but, before the work could commence, he changed his mind and issued fresh instructions in early 1542. John Rogers, a military engineer previously stationed in Guînes, was brought back to England to construct a major system of defences on the east bank of the River Humber, comprising a central castle linked to two large blockhouses.

The design of the new defences was probably carried out by Rogers and resembled his earlier work near Calais, although the King probably also made some decisions on the project personally. Sir Richard Long and Michael Stanhope were instructed to oversee the construction of the defences, with Thomas Aldred acting as the project's paymaster and William Reynolds in the role of master mason. Initial estimates suggested that 530 workers would be needed, including masons, carpenters and plumbers, but more may have been required in practice. Some of the building materials were taken from monastic institutions, which had recently dissolved by Henry; stone and lead was taken from the nearby Meaux Abbey, further stone from the friaries in Hull and probably also from St Mary's Church in Hull, which had recently collapsed. At least some of the bricks needed were made in a series of ten kilns beside the site itself. The land needed for the buildings had been seized during the dissolution of the monasteries. By December 1543, £21,056 had been spent on the project.

The castle was rectangular, with brick and stone foundations and a brick superstructure. It had two large, curved bastions containing chambers on the west and east ends, and a three-storey rectangular keep in the middle, 66 by 50 feet (20 by 15 m) across, set within an inner courtyard. The outer wall was 19 feet (5.8 m) thick and contained a gallery and ports for hand-guns, and supported two tiers of artillery. A moat ran around the outside of the castle. The two-storey tall blockhouses were also built from brick and stone, and each had a square central tower and entrance at the rear, and three curved bastions to the front and sides. Their walls were 16 feet (4.9 m) thick, sloped so as to deflect incoming fire, and supported two tiers of guns; the interiors were partitioned, to reduce the risk of explosions damaging the entire fortification. The use of bastions adopted some features from the Italian-style of defences then popular on the continent, but their design was imperfect and failed to provide flanking cover or interlink with the neighbouring defences. A crenellated curtain wall, approximately 900 metres (3,000 ft) long and 12 feet (3.7 m) high, linked the blockhouses and castle, with a wet moat on the eastward side.

After the construction, Sir Richard Long and Michael Stanhope were placed in command of the castle and blockhouses; the initial garrison may have been substantial, costing around £1,000 a year, but this was mostly demobilised at the end of 1542. Nonetheless, the castle and blockhouses still proved expensive to maintain. As a result, in 1553, an agreement was reached with the corporation of Hull, under which the town would take over responsibility for their maintenance, in exchange for an annual grant of £50 from various local manors. The town provided a bond of £2,000 as a commitment that it would keep its commitments. The mayor of Hull also took over the role of the Governor of Hull, with "keepers" were appointed by the town to run each of the buildings; the pasture land behind the fortifications was rented out to bring in income.