Saitama Prefecture (埼玉県, Saitama-ken; Japanese pronunciation: [saꜜi.ta.ma, sai.ta.maꜜ.keɴ]) is a landlocked prefecture of Japan located in the Kantō region of Honshu. Saitama Prefecture has a population of 7,338,536 (January 1, 2020) and has a geographic area of 3,797 km² (1,466 sq mi). Saitama Prefecture borders Tochigi Prefecture and Gunma Prefecture to the north, Nagano Prefecture to the west, Yamanashi Prefecture to the southwest, Tokyo to the south, Chiba Prefecture to the southeast, and Ibaraki Prefecture to the northeast.

Saitama is the capital and largest city of Saitama Prefecture, with other major cities including Kawaguchi, Kawagoe, and Tokorozawa.

According to Sendai Kuji Hongi (Kujiki), Chichibu was one of 137 provinces during the reign of Emperor Sujin. Chichibu Province was in western Saitama.

The area that would become Saitama Prefecture in the 19th century is part of Musashi Province in the Ritsuryō (or ryō-system; ritsu stands for the penal code, ryō for the administrative code) Imperial administration of antiquity (see Provinces of Japan and the 5 (go) capital area provinces (ki)/7 (shichi) circuits (dō) system) which was nominally revived in the Meiji restoration but has lost much of its administrative function since the Middle Ages. Saitama District (Saitama-gun) was one of Musashi's 21 ritsuryō districts.

In the fifth year of the Keiun era (708), deposits of copper were reported to have been found in the Chichibu District of what is now Saitama Prefecture.

The Saitama area was historically known as a fertile agricultural region which produced much of the food for the Kantō region. During the Edo period, many fudai daimyōs ruled small domains within the Saitama area.

At the end of the early modern Edo period, large parts of present-day Saitama were part of the shogunate domain (baku-ryō) or the often subsumed holdings of smaller vassals (hatamoto-ryō) around Edo, major areas were part of the fiefdoms (-han) Kawagoe (ruled by Matsui/Matsudaira, fudai), Oshi (Okudaira-Matsudaira, fudai) and Iwatsuki (Ōoka, fudai); few territories were held by domains seated in other provinces.

In the Meiji Restoration, after being briefly united with other rural shogunate territories in Musashi under Musashi governors (Musashi chikenji), many former shogunate/hatamoto territories in Northwestern Musashi became Ōmiya Prefecture (大宮県, Ōmiya-ken), soon renamed to Urawa (浦和県, -ken) in 1868/69, with some territories held by other short-lived prefectures (Iwahana [ja]/later mainly Gunma and Nirayama [ja]/later mainly Shizuoka, Kanagawa and Tokyo). In the replacement of -han with -ken, the associated territorial consolidation (removal of feudal era ex-/enclaves) and first wave of prefectural mergers in 1871/72, Oshi and Iwatsuki prefectures were merged into Urawa; after consolidation, it consisted of the entire Saitama District and Northern parts of Adachi and Katsushika (But at that time, "major and minor districts", 大区, daiku and 小区, shōku, served as administrative subdivisions) and was renamed to Saitama. The government of the prefecture was to be set up in Iwatsuki Town, Saitama District in November 1871 by the Dajōkan ordinance to set up the prefecture, but ultimately remained in Urawa's previous prefectural government seat in Urawa Town in Adachi District.