Blandford Forum (/ˈblænfərd/ BLAN-fərd) is a market town in Dorset, England, on the River Stour, 13 miles (21 km) north-west of Poole. It had a population of 10,355 at the 2021 census.

The town is notable for its Georgian architecture, the result of rebuilding after a major fire in 1731; it was assisted by an Act of Parliament and a donation by George II, to designs by local architects John and William Bastard.

The town's economy is based on a mix of the service sector and light industry. Blandford Camp, a military base, is on the hills two mi (three km) north-east of the town. It is the base of the Royal Corps of Signals, the communications wing of the British Army, and the site of the Royal Signals Museum.

Blandford has been a fording point on the River Stour since Anglo-Saxon times. The name Blandford derives from the Old English blǣge, and probably means ford where gudgeon or blay are found. The name Blaneford or Bleneford is recorded in the Domesday Book, referring not to Blandford Forum itself but to the adjacent villages of Bryanston and Blandford St Mary on the opposite side of the ford, and Langton Long Blandford further downstream.

By the 13th century, the settlement on the north bank of the river had become a market town^{[citation needed]} with a livestock market serving the nearby Blackmore Vale with its many dairy farms. At the start of the 14th century, it returned two members of parliament and was also known as Cheping Blandford, where Cheping or Chipping refers to a market. The Latin translation Forum was first recorded in 1540.

In Survey of Dorsetshire, written by Thomas Gerard of Trent in the early 1630s, Blandford was described as "a faire Markett Towne, pleasantlie seated upon the River ... well inhabitted and of good Traffique". In the 17th-century English Civil War Blandford was a Royalist centre; most inhabitants supported the king.

In the 18th century Blandford was one of several lace-making centres in the county; Daniel Defoe stated that lace made in the town was "the finest bonelace in England... I think I never saw better in Flanders, France or Italy". In the 17th and 18th centuries Blandford was also a malting and brewing centre of some significance.

Almost all of Blandford's buildings were destroyed on 4 June 1731 by the "great fire", which was the last of several serious fires that occurred in the 16th, 17th and 18th centuries. The fire began in a tallow chandler's workshop on a site that is now The King's Arms public house. Within a few hours, almost 90% of the town's fabric had gone; all fire-fighting equipment had been lost to the fire and the church's lead roof had melted. Even properties west of the river in Blandford St Mary and Bryanston were burned, though notable buildings that survived in the town include the Ryves Almshouses and Dale House in Salisbury Street, Old House in The Close, and much of East Street, including Stour House. An Act of Parliament was introduced that stated that rebuilding work must be in brick and tile and should begin within four years. With assistance from the rest of the country—including £1,000 given by King George II—the town was rebuilt over the next ten years to the designs of local architects John and William Bastard. Bottlenecks were removed and streets realigned in the new town plan, which also provided a wider market place. As well as residential and commercial property, new buildings included a new town hall, school and church. The redesigned town centre has survived to the present day virtually intact.