The Port of Tilbury is located on the River Thames at Tilbury in Essex, England. It is the principal port for London, as well as being the main United Kingdom port for handling the importation of paper. There are extensive facilities for containers, grain, and other bulk cargoes. There are also facilities for the importation of cars. It forms part of the wider Port of London.

     Tilbury lies on the north shore of the River Thames, 25 miles (40 km) downstream of London Bridge, at a point where the river makes a loop southwards, and where its width narrows to 800 yards (730 m). The loop is part of the Thames lower reaches: within the meander was a huge area of marshland. Gravesend on the opposite shore had long been a port of entry for shipping, all of which had used the river itself for loading and unloading of cargo and passengers. There was also a naval dockyard at Northfleet. The new deepwater docks were an extension of all that maritime activity.

The original docks of London, all built close to the City, were opened in stages by what was to become the East and West India Docks Company (E&WIDC) at the beginning of the 19th century. With the coming of the railways and increasing ship size, location close to the centre of London became less important than access to deep water, unrestricted sites and reduction in time spent travelling up the winding Thames. The Company had long been in competition with their rival, the London and St Katherine Dock Company (L&StKDC), and had been doing all it could to dominate it. The opening of the Royal Albert Dock by the L&StKDC, with its deepwater quayage, in 1880 had given access to the Thames at Gallions Reach, 11 miles (18 km) by river below London Bridge and downstream of the then principal London docks. The E&WIDC were forced to retaliate.

In 1882, an Act of Parliament allowed the latter to construct the docks at Tilbury; work began a fortnight later, and the first vessel to enter the docks was on 17 April 1886. This was the Glenfruin carrying the official party for the opening ceremony. The opening of the dock took place at the beginning of the steamship era, and its location soon proved to be the correct one.

The original docks consisted of a tidal basin on Gravesend Reach opposite Northfleet, connected by a lock to a main dock with three side branches named East, Central and West Branch docks. Between the tidal basin and Main Dock were two dry docks

In 1909 Tilbury, along with the upstream docks, became part of the newly established Port of London Authority (PLA).

In 1921, and again in 1929, the PLA carried out major improvements. These included a new lock 1,000 feet (300 m) long and 110 ft (34 m) wide, linking the docks directly to the Thames to the west at Northfleet Hope, and a third dry dock, 752 feet (229 m) long and 110 feet (34 m) wide. These works were carried out by Sir Robert McAlpine.

During the 1960s, at the time when the upstream docks were closing, the PLA further extended the Tilbury dock facilities. Between 1963–1966 a huge fourth branch dock, running north from Main Dock for nearly 1 mile (1.6 km), was constructed. The tidal basin was closed and eventually filled in. In 1969 a £6M riverside grain terminal on Northfleet Hope (at the time the largest in Europe) was brought into use. By the early 1980s Tilbury was the last set of enclosed docks in operation by the PLA.

The PLA funded a new £30M container port which opened in 1967. Labour issues prevented full service from starting until April 1970, although United States Lines reached an agreement with the union to begin service in 1968. In 1978, a deep water riverside berth was opened for large container ships on reclaimed land at Northfleet Hope.

In 1992 the port was privatised and is part of the Forth Ports organisation, the PLA retaining the role of managing the tidal Thames.

Today the port handles a variety of bulk cargo, timber, cars and container traffic and remains, along with Southampton and Felixstowe, one of Britain's three major container ports. It is the main UK port for importing paper including newsprint.

The Port of Tilbury Police, among the oldest of such forces in the UK, are responsible for the security of the Port.

The port is also a base of operations of Thurrock Sea Cadets, who operate out of TS Iveston (a Coniston class former minesweeper ).

Seafarers welfare charity, Apostleship of the Sea, which provides practical and pastoral support to seafarers, has a port chaplain based at the port.