Bang Sue (Thai: บางซื่อ, pronounced [bāːŋ sɯ̂ː]) is one of the 50 districts (khet) of Bangkok, Thailand. It borders Chatuchak to the east, Phaya Thai to the southeast, Dusit to the south, Bang Phlat and Bang Kruai across the Chao Phraya to the west and Mueang Nonthaburi to the north.

Bang Sue was one of eight outer Bangkok amphoes (districts) established during King Chulalongkorn's reign.

In an administrative reform in 1938, Bang Sue was reduced from an amphoe to a tambon (sub-district), becoming part of Dusit district. In 1972, as part of the creation of a special administrative area of Bangkok where tambons in Bangkok were renamed khwaengs and amphoes in Bangkok were renamed khets, Bang Sue became Khwaeng Bang Sue under Khet Dusit. Bang Sue became a khet in 1989.

"Bang Sue" means "community of the faithful". The name appears in Journey to Phrabat, a poem by Sunthorn Phu written in 1807.

According to regional folklore, the name originates from the "Story of Lord Uthong". When someone asked about the hidden treasure of Lord Uthong (a mythical king, not the King Uthong of Ayutthaya), the locals responded with honesty.

Bang Pho is the historic area along the Chao Phraya River. In the 18th century, corresponding to the early Rattanakosin era, used to be a settlement for Annamese (presently known Vietnamese) immigrants.

Rama VI Bridge was the first bridge to cross the Chao Phraya River. It was opened on 1 January 1923 and was named after King Vajiravudh (Rama VI). The 442 metre (1450 ft) long and 10 metre (33) wide road-rail bridge originally carried a single-track railway to the west and south of Thailand and a one-lane road.

During World War II the bridge was heavily damaged by Allied bombing, since it was being used by the occupying Japanese. The reconstructed bridge was re-opened on 12 December 1953. In 1992, road traffic was permanently diverted to the new Rama VII bridge slightly upstream as the State Railway of Thailand converted the roadway to a second railway track.