Sinŭiju (Korean: 신의주시; MR: Sinŭiju-si; IPA: [ɕinɰidzu ɕi]) is a city in North Korea which faces Dandong, Liaoning, China, across the international border of the Yalu River. It is the capital of North P'yŏngan province. Part of the city is included in the Sinŭiju Special Administrative Region, which was established in 2002 to experiment with introducing a market economy. In recent years the city has seen increasing tourism from China.

Sinŭiju is bordered by the Amnok River, and by P'ihyŏn and Ryongch'ŏn counties. The city's altitude is 1 metre (4 feet) above sea level. There are several islands at the mouth of the Amnok River - Wihwa-do, Rim-do, Ryuch'o-do and Tongryuch'o-do.

Sinuiju city is the heart of the Sinuiju Special Administrative Region. The city is currently divided into 49 tong (neighbourhoods) and 9 ri (villages):

Developed as a major settlement during Japanese colonial rule at the terminus of a railway bridge across the Amrok River, Sinuiju is located 11 km (7 miles) south by southwest of Ŭiju, the old city from whose name Sinŭiju (meaning “New Ŭiju”) derives. As an open port, it grew commercially with the logging industry which uses the Amnok River to transport lumber. Additionally, a chemical industry developed after the hydroelectric Sup'ung Dam was built further up the river.

During the Korean War, after being driven from P'yŏngyang, Kim Il Sung and his government temporarily moved the capital to Sinŭiju - although as United Nations Command forces approached, the government again moved - this time to Kanggye. On 7 November 1950, the city sustained heavy damage during an aerial bombardment from the United States Air Force; 95 percent of the city was destroyed. However, the city has since been rebuilt.

In 2018, a master plan for the redevelopment of the city was unveiled and shown to Kim Jong Un, which would have featured many high rise buildings and parks, centered around the road leading to the statues of Kim Il Sung and Kim Jong Il. Ultimately, this plan has yet to be fulfilled, with the only major work completed being the repaving of roads leading to the statues and the red coloured, circular apartment building behind and the Sinuiju Youth Open Air Theatre's completion, although the industrial areas in the city have seen some reconstruction.

An important light industry centre in North Korea, Sinŭiju has a plant manufacturing enamelled ironware as well as a textile mill, paper mill and an afforestation factory. Its southwest harbour has a shipyard, although the shipyard's main function is seemingly to dismantle ships for scrap metal and other usable materials rather than building new ships. The area has recycling plants which recycle a wide range of material, including products that are banned for recycling in China. The Sinŭiju Cosmetics Factory is located in South Sinŭiju (Namsinŭiju).

A substantial portion of North Korea's international trade, both legal and illegal, passes through Sinuiju and Dandong, across the Yalu River.