Royal Navy Dockyards (more usually termed Royal Dockyards) were state-owned harbour facilities where ships of the Royal Navy were built, based, repaired and refitted. Until the mid-19th century the Royal Dockyards were the largest industrial complexes in Britain.

From the reign of Henry VII up until the 1990s, the Royal Navy had a policy of establishing and maintaining its own dockyard facilities (although at the same time, as continues to be the case, it made extensive use of private shipyards, both at home and abroad). Portsmouth was the first Royal Dockyard, dating from the late 15th century; it was followed by Deptford, Woolwich, Chatham and others. By the 18th century, Britain had a string of these state-owned naval dockyards, located not just around the country but across the world; each was sited close to a safe harbour or anchorage used by the fleet. Royal Naval Dockyards were the core naval and military facilities of the four Imperial fortresses - colonies which enabled control of the Atlantic Ocean and its connected seas. The Royal Dockyards had a dual function: ship building and ship maintenance (most yards provided for both but some specialised in one or the other). Over time, they accrued additional on-site facilities for the support, training and accommodation of naval personnel.

For centuries, in this way, the name and concept of a Royal Dockyard was largely synonymous with that of a naval base. In the early 1970s, following the appointment of civilian Dockyard General Managers with cross-departmental authority, and a separation of powers between them and the Dockyard Superintendent (commanding officer), the term 'Naval Base' began to gain currency as an official designation for the latter's domain.^{[citation needed]} 'Royal Dockyard' remained an official designation of the associated shipbuilding/maintenance facilities until 1997, when the last remaining Royal Dockyards (Devonport and Rosyth) were fully privatised.

Most Royal Dockyards were built around docks and slips. Traditionally, slipways were used for shipbuilding, and dry docks (also called graving docks) for maintenance; (dry docks were also sometimes used for building, particularly pre-1760 and post-1880). Regular hull maintenance was important: in the age of sail, a ship's wooden hull would be comprehensively inspected every 2–3 years, and its copper sheeting replaced every 5. Dry docks were invariably the most expensive component of any dockyard (until the advent of marine nuclear facilities). Where there was no nearby dock available (as was often the case at the overseas yards) ships would sometimes be careened (beached at high tide) to enable necessary work to be done. In the age of sail, wharves and capstan-houses were often built for the purpose of careening at yards with no dock: a system of pulleys and ropes, attached to the masthead, would be used to heel the ship over giving access to the hull.

In addition to docks and slips, a Royal Dockyard had various specialist buildings on site: storehouses, sail lofts, woodworking sheds, metal shops and forges, roperies (in some cases), pumping stations (for emptying the dry docks), administration blocks and housing for the senior dockyard officers. Wet docks (usually called basins) accommodated ships while they were being fitted out. The number and size of dockyard basins increased dramatically in the steam era. At the same time, large factory complexes, machine-shops and foundries sprung up alongside for the manufacture of engines and other components (including the metal hulls of the ships themselves).

One thing generally absent from the Royal Dockyards (until the 20th century) was the provision of naval barracks. Prior to this time, sailors were not usually quartered ashore at all, they were expected to live on board a ship (the only real exception being at some overseas wharves where accommodation was provided for crews whose ships were being careened). When a ship was decommissioned at the end of a voyage or tour of duty, most of her crew were dismissed or else transferred to new vessels. Alternatively, if a vessel was undergoing refit or repair, her crew was often accommodated on a nearby hulk; a dockyard often had several commissioned hulks moored nearby, serving various purposes and accommodating various personnel, including new recruits. Things began to change when the Admiralty introduced more settled terms of service in 1853; nevertheless, thirty years were to pass before the first shore barrack opened, and a further twenty years before barracks at all three of the major home yards were finally completed. Through the course of the 20th century these barracks, together with their associated training and other facilities, became defining features of each of these dockyards.

In 1985 Parliament was given the following description of the functions of the two then remaining Royal Dockyards: "The services provided by the royal dockyards at Devonport and Rosyth to the Royal Navy fall into five main categories as follows: (a) Refit, repair, maintenance and modernisation of Royal Navy vessels; (b) Overhaul and testing of naval equipments, including those to be returned to the Director General of Stores and Transport (Navy) for stock and subsequent issue to the Royal Navy; (c) Installation and maintenance of machinery and equipment in naval establishments; (d) Provision of utility services to Royal Navy vessels alongside in the naval base and to adjacent naval shore establishments; and (e) manufacture of some items of ships' equipment".

For a long time, well into the eighteenth century, a Royal Dockyard was often referred to as The King's Yard (or The Queen's Yard, as appropriate). In 1694, Edmund Dummer referred to "His Majesty's new Dock and Yard at Plymouth"; from around that time, HM Dock Yard (or HM Dockyard) increasingly became the official designation. While, as this phrase suggests, the primary meaning of 'Dockyard' is a Yard with a Dock, not all dockyards possessed one; for example, at both Bermuda and Portland dry docks were planned but never built. Where a dock was neither built nor planned (as at Harwich, Deal and several of the overseas yards) the installation was often designated HM Naval Yard rather than 'HM Dockyard' in official publications (though the latter term may have been used informally); they are included in the listings below.