Borough High Street is a road in Southwark, London, running south-west from London Bridge, forming part of the A3 route which runs from London to Portsmouth, on the south coast of England.

Borough High Street continues southwest as Newington Causeway, here co-inciding with ancient Stane Street, the Roman road between London and Chichester. Another important connection is with the Dover Road (the modern A2 route) which diverges in a south-east direction from Borough High Street at a junction of five roads adjacent to Borough Underground station as Great Dover Street. The Dover Road mostly follows the alignment of Roman Watling Street, though, here, the original Roman route was along Tabard Street closely parallel with Great Dover Street to the north.

The stretch of Borough High Street south of the junction with Long Lane, Marshalsea Road, and Tabard Street, where stands the ancient church of St. George the Martyr, was formerly called Blackman Street after a long resident family there.

Borough Market was once held on the street, but has been moved to the west with its main entrance on Southwark Street. Southwark Cathedral, prominent on the west side of the street near London Bridge, can be reached by a small pedestrian bridge and stairs, though its postal address is actually Montague Close.

The earliest recorded name for the street is simply 'The Borough' which was the part between the fork of the street and London Bridge. South of the fork it was called 'St. Margaret's Hill'. These names were subsumed in the Tudor period as 'Longe Southwark' (differentiated from 'Short Southwark' now Tooley Street) and by the late Georgian era as simply 'High Street' and the northern section from the junction with Duke Street Hill was renamed 'Wellington Street' to commemorate the Duke of Wellington. From the 1890s the London County Council started to rationalise all metropolitan street names and 'Borough High Street' became the name for the current route.

Before the building of Westminster Bridge, Borough High Street was the only connection from the south bank of the Thames to London, which lay on the north bank. As a major communications node for traffic between London and Portsmouth, Dover, south-east England generally and also travellers from Europe, Borough High Street had many coaching inns. These were of considerable size, with courtyard and surrounding multi-tier galleries. There were twenty-three in total, including the Bear, the Queen's Head, the King's Head, the Catherine Wheel, the Tabard, the White Hart, and the George. Many of them dated back originally to the mediæval period, and were in use as coaching inns up to the mid-nineteenth century, when this mode of transport was superseded by the railway. These inns were very famous and receive mention in the work of such literary giants as Chaucer, Shakespeare and Charles Dickens, though are now all gone - apart from the George.

On the west side of the street, the modern office block called Brandon House at 180 Borough High Street (opposite Borough Underground station) marks the site of a mansion called Suffolk Place, demolished in 1557. It is depicted by Anthony van den Wyngaerde's sixteenth century Panorama of London, which features Borough High Street prominently in the foreground of the picture. After demolition the site of the mansion and the area to the west of Borough High Street here became notorious as the criminal enclave of The Mint.

The Marshalsea and King's Bench Prisons were also located on Borough High Street on the east side between Newcomen Street and Tabard Street.