The Borough of Swindon is a unitary authority area with borough status in Wiltshire, England. Centred on Swindon, it is the most north-easterly district of South West England.

The first borough of Swindon was a municipal borough, created in 1900 as a merger of the two urban districts of Old Swindon and New Swindon.

In 1974 the borough of Thamesdown was created under the Local Government Act 1972. Thamesdown covered the areas of the municipal borough of Swindon and the neighbouring Highworth Rural District (which had been created in 1894), which were both abolished at the same time. Thamesdown was a lower-tier non-metropolitan district, with Wiltshire County Council being the higher-tier authority for the area. Thamesdown was given borough status from its creation, allowing the chair of the council to take the title of mayor.

On 1 April 1997 Thamesdown was made a unitary authority, making it administratively independent from Wiltshire County Council. In June 1996, during the transition period to becoming a unitary authority, the council passed an order that the area would be renamed Swindon with effect from 1 April 1997 as well. The former Thamesdown name and logo continued to be used by the municipal bus operator, Thamesdown Transport, until 2017 when it was sold and renamed to "Swindon's Bus Company". Swindon remains part of the ceremonial county of Wiltshire for the purposes of lieutenancy.

The borough of Swindon occupies an area forming the north east corner of Wiltshire and is bordered by two other counties, Gloucestershire (to the north) and Oxfordshire (to the east). West Berkshire is also only a short distance from the borough's south eastern tip. The generally hilly landscape is sculpted by the upper Thames guiding the northern border, small tributaries draining into the Thames, and the Marlborough Downs rising toward the south.

The borough encompasses the Swindon urban area and surrounding countryside to the north, east and south, including the town of Highworth. It comprises the former Swindon Municipal Borough and a further 18 civil parishes:

• Bishopstone (with Hinton Parva)
• Blunsdon
• Castle Eaton
• Chiseldon
• Covingham
• Hannington
• Haydon Wick
• Highworth (town and surrounding district, including Sevenhampton)
• Inglesham
• Liddington
• Nythe, Eldene and Liden
• St Andrews
• South Marston
• Stanton Fitzwarren
• Stratton St Margaret
• Wanborough
• West Swindon
• Wroughton

Since 1 April 2017 the entire Borough has been parished, following the establishment of West Swindon parish and the creation of Central Swindon North and Central Swindon South (styled by its parish council as South Swindon). The two Central parishes fall within the boundaries of the town and former municipal borough, divided along the Great Western Main Line railway.

At the same time:

• the part of Chiseldon parish north of the M4, including the former hamlet of Coate, was transferred to Central Swindon South;
• the parish of Blunsdon St Andrew was divided into St Andrews and Blunsdon, the A419 forming the boundary between them;
• the parish of Nythe was expanded to form Nythe, Eldene and Liden.

The council follows a leader and cabinet model and has 57 members elected by 20 wards. Elections are held in three out of every four years, with one-third of the seats being elected at each election. From the first election in 1996 to the 2000 election, Labour had a majority on the council. Following a period where no party had a majority, the Conservatives gained a majority at the 2003 election and had control until the 2023 election, when Labour took control.

The borough is divided into three Parliamentary constituencies. Swindon North and Swindon South are wholly within the boundaries of the borough of Swindon, while East Wiltshire includes the Swindon borough council wards of Wroughton & Wichelstowe and Ridgeway, and the parish of Chiseldon. Swindon North and Swindon South are seen as key marginal seats at general elections, having been bellwether seats since 1997 when their predecessor constituencies were created; currently both seats are held by the Labour Party. East Wiltshire is currently held by the Conservative Party.

The borough was one of the first areas to declare in the 2016 European Union membership referendum. 61,745 (54.3%) voters supported leaving the European Union, whilst 51,220 (45.7%) wished to remain.

• Swindon Borough Council elections