Pirbright (/ˈpɜːrbraɪt/) is a village in Surrey, England. Pirbright is in the borough of Guildford and has a civil parish council covering the traditional boundaries of the area. Pirbright contains one buffered sub-locality, Stanford Common near the nation's farm animal disease research institute. The village's grade II* listed medieval church has a large Boulder grave for explorer Henry Morton Stanley. The nearby section of Hodge Brook is also known as the Congo Stream, between Ruwenzori Hills and Stanley Pool.

Pirbright has two communities: army training barracks and designated homes are north of a London main axis (south-west) railway and the slightly dispersed village is south. The village is almost entirely surrounded by heathland, much of it owned by the Ministry of Defence and used by the Army Training Centre Pirbright. The south and south-east of the parish is mostly woodland and has three small farms. The south-west of the parish has a large military training area, Pirbright Common. Near to the church are several features due to Stanley's association with the village: Hodge Brook is equally marked as Congo Stream, between Ruwenzori Hill and Stanley Hill. Mazamboni Farm is next to Aruwimi Wood.

Its name had three medieval variants (each involving the letter 'f' where there is currently a 'b'). It came from Anglo-Saxon (Old English) Pirige-fyrhþ = "sparse woodland where peartrees grow".

The manor of Pirbright does not seem to occur earlier than the 13th century, when it was reported to be held of the honour of Clare by Peter de Pirbright. John Trenchard died seised of it (holding) under the Earl of Gloucester in 1301–2. In this time it had a medieval deer park, disparked under Richard II. During the reign of Henry VIII the manor changed hands several times: it formed part of the marriage portion of Queen Katharine of Aragon and was successively in the possession of Sir Thomas Boleyn and Sir William Fitz William. Finally it was granted to Sir Anthony Browne, afterwards Viscount Montagu, with whose family it remained until the middle of the next century.

The locality saw development in the form of brick labourers' cottages with a few Georgian large homes, some with modest estates of land. Of the last sort, Vice-Admiral the Hon. John "Foulweather Jack" Byron, explorer, grandfather of George Gordon Byron, 6th Lord Byron (usually known as 'the poet, Lord Byron') planted in the late 18th century an avenue of Scotch pines to the foot of a tower hill, Crown Prince Hill, in the woods, still called Admiral's Walk or 'road', which extends for 1 mile (1.6 km), half within the Danger Area owned by the Ministry of Defence of Pirbright Common.

Heatherside was the early 20th century home of F. C. Selous, the African big-game hunter, and contained a "remarkable collection of hunting spoils and native African curiosities."

Pirbright's traditional churchyard contains the large block of granite, 11-feet high, marking the grave of British Empire soldier and explorer Henry Morton Stanley, who died in London aged 63. This is partly inscribed with the words "Henry Morton Stanley Bula Matari 1841–1904 Africa". Bula Matari was another of his names and translates as "Breaker of Rocks" or "Breakstones" in Kongo.

A large fire occurred in the area in April 2022.