Bang Rak (Thai: บางรัก, pronounced [bāːŋ rák]) is a khwaeng (subdistrict) and historic neighbourhood in Bangkok's Bang Rak District. It lies between the Chao Phraya River and Charoen Krung Road, and was home to communities of European expatriates who settled in the area mostly during the second half of the 19th century as Siam (as Thailand was then known) opened up to the West. Among them were the Portuguese, French and British, whose embassies occupied extensive grounds in the area, Danes who founded shipping companies as well as the historic Oriental Hotel, and Catholic missionaries who established some of the first schools in the country on the grounds surrounding Assumption Cathedral.

Bang Rak was among the city's busiest commercial neighbourhoods at the turn of the 19th–20th centuries, but declined in prominence as newer development soon moved elsewhere. Beginning in the 2010s, urban revitalization efforts have led the area to become known as the Charoenkrung Creative District, a project led by the Thailand Creative & Design Center, which re-established its headquarters at the Grand Postal Building in 2017.

When Bangkok became capital of the Rattanakosin Kingdom in 1782, fringe communities developed outside its city walls, mainly along the banks of the Chao Phraya River. Downstream of the walled city beyond the Chinese community of Sampheng, the river's eastern bank became home to several ethnic communities, including Portuguese and Chinese Catholics centred around the Holy Rosary Church, Malays, and Vietnamese refugees led by the future Emperor Gia Long. The area gradually attracted European visitors, beginning with French Catholic missionaries, who eventually took over the management of the church. They also founded a new church (later to become the Assumption Cathedral) some distance further south in 1822, and based their mission offices there. They were followed by Protestants, mainly Americans, in the 1830s. Portugal was the first foreign nation to establish a consulate in the capital, having been granted a piece of land in the area in 1820.

When King Mongkut (Rama IV) ascended the throne in 1851, the city had grown beyond its original walls, and Khlong Phadung Krung Kasem was dug in 1852 to extend the city's periphery. The canal separated the riverside communities, with the Chinese neighbourhood of Talat Noi on the city side, and the Portuguese Consulate and Assumption Church on the other, which later became known as Bang Rak. The origins of the name are unclear, though two prevailing theories posit that it derived either from that of the rak (Gluta usitata) tree, a large trunk of which had been found in the area, or from the word rak (รักษ์ 'heal'), after hospitals operated by the area's missionaries. Western communities were encouraged to settle here, and consulates were established in the area as Siam signed trade treaties with European powers, beginning with the British, whose consulate was built next to Portugal's in 1857. The French followed soon after. Charoen Krung Road, the country's first modern road, was built to serve the area in 1862, following a petition by the consuls.

The advent of land-based transport transformed the city, and Charoen Krung Road became its first main thoroughfare. As the country continued to modernize under Mongkut's successor King Chulalongkorn (Rama V, r. 1868–1910), Western values became expressed through the architecture of public and private buildings. In Bang Rak, several were built in various Western styles from the late-18th to early-19th centuries, including the Customs House and the original building of Assumption College (one of the first schools in the country, founded by the Catholic Mission), both completed in grand Palladian style in 1890. Many private enterprises were established in the area, including the famous luxury hotel the Oriental. By the turn of the century, Bang Rak had become a busy commercial hub in addition to Bangkok's main expatriate neighbourhood, a busy conglomeration of residences, shops, diplomatic and business offices, as well as rice mills, sawmills, warehouses and a harbour.

Bang Rak's economic prominence gradually declined as newer development shifted elsewhere during the 20th century. In the 21st century, increasing interest in cultural tourism led to a renewed interest in the architectural and historic sites of Bang Rak and neighbouring Talat Noi. The 2010s saw the neighbourhood become the focus of urban revitalization efforts aiming to revive the area as a creative district. Galleries, public artworks, and "hip" cafes are now scattered throughout the neighbourhood. The project is supported by the Thailand Creative & Design Center, which re-established its headquarters at the Grand Postal Building (built in 1940 on the former site of the British consulate) in 2017, though concerns remain over the trend towards gentrification and the encroachment of development.

Bang Rak Subdistrict occupies an elongated strip of land between Chao Phraya River to the west and Charoen Krung Road on the east. It is bounded by Khlong Phadung Krung Kasem to the north, across which lies the Talat Noi neighbourhood of Samphanthawong District, and Khlong Sathon to the south, across which is the district of Sathon. The other subdistricts of Bang Rak District—Maha Phruettharam, Si Phraya, Suriyawong and Si Lom—all border it on the east, while across the River lies Khlong San District. The subdistrict's area totals 0.689 square kilometres (0.266 sq mi).