Hongkou District (simplified Chinese: 虹口区; traditional Chinese: 虹口區; pinyin: Hóngkǒu Qū; Shanghainese: ghon¹kheu² chiu¹) is a northern district of Shanghai proper, People's Republic of China. It has a land area of 23.48 km² (9.07 sq mi) and a population of 799,700 as of 2001.

It is the location of the Astor House Hotel, Broadway Mansions, Lu Xun Park and the Lu Xun memorial.

Hongkou is home to the Shanghai International Studies University (SISU) and the Shanghai University of Finance and Economics. Fuxing High School and Shanghai Foreign Language School Affiliated to SISU (SFLS) are the best high schools in this area.

During the Second World war when the city was occupied by the Japanese, 20,000 Jewish refugees from Nazi-occupied Europe lived in a notoriously overcrowded square-mile section known to the West as the Shanghai ghetto.

Richard Evans, author of Deng Xiaoping and the Making of Modern China (first edition 1993) said that he used the spelling Hongkew for Hongkou in his book, along with other older spellings, because that name had been used for Anglophones for a long period of time and "to continue to use them is comparable to go on to using Vienna for Wien or Venice for Venezia."