Zhytomyr (Ukrainian: Житомир [ʒɪˈtɔmɪr] ^ⓘ; see below for other names) is a city in the north of the western half of Ukraine. It is the administrative center of Zhytomyr Oblast (province), as well as the administrative center of the surrounding Zhytomyr urban hromada (commune) and Zhytomyr Raion (district). Moreover Zhytomyr consists of two urban districts: Bohunskyi District and Koroliovskyi District (named in honour of Sergey Korolyov). Zhytomyr occupies an area of 65 square kilometers (25 sq mi). Its population is 261,624 (2022 estimate).

Zhytomyr is a major Ukrainian transport hub as the city lies on a historic route linking the city of Kyiv with the west through Brest. Today it links Warsaw with Kyiv, Minsk with Izmail, and several major cities of Ukraine. Zhytomyr was also the location of Ozerne airbase, a key Cold War strategic aircraft base 11 kilometers (6.8 mi) southeast of the city.

Important economic activities of Zhytomyr include lumber milling, food processing, granite quarrying, metalworking, and the manufacture of musical instruments.

Zhytomyr Oblast is the main center of the Polish minority in Ukraine, and in the city itself there is a Latin Catholic cathedral and large Roman Catholic Polish cemetery, founded in 1800. It is regarded as the third biggest Polish cemetery outside Poland, after the Lychakivskiy Cemetery in Lviv and Rasos Cemetery in Vilnius.

The city of Zhytomyr is also historically known by different names in other languages:

Legend holds that Zhytomyr was established about 884 by Zhytomyr, prince of a Slavic tribe of Drevlians. This date, 884, is cut into a large stone of the ice age times, standing on the hill where Zhytomyr was founded. Zhytomyr was one of the prominent cities of Kievan Rus'. The first records of the town date from 1240, when it was sacked by the Mongol hordes of Batu Khan.

In 1320 Zhytomyr was captured by the Grand Duchy of Lithuania and received Magdeburg rights in 1444. After the Union of Lublin (1569) the city was incorporated into the Kingdom of Poland and became an important center of local administration, seat of the starosta, and capital of Żytomierz County. Here, sejmiks of Kiev Voivodeship took place. In 1572, the town had 142 buildings, a manor house of the starosta and a castle. Following the privilege of King Sigismund III Vasa, Zhytomyr had the right for two fairs a year. During Khmelnytsky Uprising (1648) Zhytomyr was incorporated into Cossack Hetmanate state. In 1667, following the Treaty of Andrusovo, it became the capital of the Kiev Voivodeship. In 1724, a Jesuit school and monastery were opened here. By 1765, Zhytomyr had five churches, including 3 Roman Catholic and 2 Orthodox, and 285 houses. In the Second Partition of Poland in 1793 it passed to Imperial Russia and became the capital of the Volhynian Governorate. In 1804 was named capital of the Volhynian Governorate.

During a period of Ukrainian independence (1917-1920) in 1918, the city was the national capital of Ukrainian People's Republic for a few weeks. Ultimately, the Ukrainian fight for independence failed and Ukrainian People's Republic became occupied by Soviet Union. A new Soviet Ukraine state was formed under Soviet rule - Ukrainian Soviet Socialist Republic. From 1920 Zhytomyr was a part of Ukrainian Soviet Socialist Republic.