Setagaya (世田谷区, Setagaya-ku, officially called Setagaya City or the City of Setagaya) is a special ward in the Tokyo Metropolis in Japan. It is also the name of a neighborhood and administrative district within the ward. Its official bird is the azure-winged magpie, its flower is the fringed orchid, and its tree is the Zelkova serrata.

Setagaya has the largest population and second-largest area (after Ōta) of Tokyo's special wards. As of July 1, 2023, the ward has an estimated population of 940,071, and a population density of 16,194 persons per km² with the total area of 58.06 km².

As of 2023, the female life expectancy in Setagaya is 88.9 years.

Setagaya is located at the southwestern corner of the Tokyo's special wards and the Tama River separates the boundary between Tokyo Metropolis and Kanagawa Prefecture.

Residential population is among the highest in Tokyo as there are many residential neighbourhoods within Setagaya. Setagaya is served by various rail services providing frequent two- to three-minute headway rush-hour services to the busiest train terminals of Shinjuku and Shibuya as well as through service trains which continue travelling on to the Tokyo Metro lines providing direct access to the central commercial and business districts. Most rail lines run parallel from east to west and there are no north to south rail services within Setagaya, except for Setagaya Line light rail.

The ward is divided into five districts. These are Setagaya, Kitazawa, Tamagawa, Kinuta and Karasuyama. The main ward office and municipal assembly (city hall) is located in Setagaya District, but other districts also have their own branch ward offices as a part of the administrative structure. Each branch office provides almost identical services as the main office, but does not provide the services related to municipal assembly.

Most of the land is in the Musashino Tableland. The parts along the Tama River to the south are comparatively low-lying.

The special ward of Setagaya was founded on March 15, 1947.

During the Edo period, 42 villages occupied the area. With the abolition of the han system in 1871, the central and eastern portions became part of Tokyo Prefecture while the rest became part of Kanagawa Prefecture; in 1893, some areas were transferred to Tokyo Prefecture. With the establishment of Setagaya Ward (an ordinary ward) in the old Tokyo City in 1932, and further consolidation in 1936, Setagaya took its present boundaries.

During the 1964 Summer Olympics, the district of Karasuyama-machi in Setagaya was part of the athletics marathon and 50 km walk event.

• Tama River
• Todoroki Valley [ja] (Yazawa River [ja])

• Futako Tamagawa Park [ja]
• Hanegi Park [ja]
• Kinuta Park
• Kitami Friendship Square
• Komazawa Olympic Park
• Okura Sports Park [ja]
• Roka Kōshun-en [ja]
• Setagaya Park [ja]
• Soshigaya Park [ja]
• Tamagawa Nogemachi Park
• Tokyo Equestrian Park

• Gotoh Museum
• Hasegawa Machiko Art Museum
• Honda Theater [ja]
• Oya Soichi Bunko, a private library of Japanese magazines for researchers and journalists
• Setagaya Art Museum
• Setagaya Daikan Yashiki [ja], a daikan's office built in 1737, an Important Cultural Property of Japan
• Setagaya Literary Museum
• Setagaya Local History Museum [ja]
• Setagaya Public Theatre [ja]
• Tokyo University of Agriculture Food and Agriculture Museum

• Gōtoku-ji, a Zen temple known as birthplace of maneki-neko, with grave of Ii Naosuke who was assassinated in the Sakuradamon Incident in 1860
• Kuhonbutsu Jōshin-ji, a Buddhist temple on Okusawa Castle [ja] ruins
• Catholic Seta Church, Seta Monastery
• Setagaya Hachimangū [ja], a Shintō shrine, a major religious centre from the late Heian period to the end of the Edo period
• Shōin shrine
• Todoroki Fudōson [ja]
• Zenyōmitsu-ji

• Carrot Tower
• Futako-Tamagawa Rise
• NHK Science & Technology Research Laboratories
• Setagaya Business Square [ja] (SBS)
• Setagaya Castle ruins
• Toho Studios
• Tokyo Metropolitan Matsuzawa Hospital

Karasuyama Area

Kinuta Area

Kitazawa Area

Setagaya Area

Tamagawa Area

Notes:
– 4-chōme (33-ban to 39-ban)
– 1, 2, 3-chōme, 4-chōme (1-ban to 32-ban)
– 1, 2-chōme
– 3, 4-chōme

• Keio Corporation
  • Keiō Line: Daitabashi, Meidai-mae, Shimo Takaido, Sakura Josui, Kami Kitazawa, Hachiman Yama, Roka Koen, Chitose-Karasuyama Stations
  • Keio Inokashira Line: Ikenoue, Shimo-Kitazawa, Shindaita, Higashi-Matsubara, Meidaimae Stations
• Odakyu Electric Railway
  • Odawara Line: Higashi-Kitazawa, Shimo-Kitazawa, Setagaya-Daita, Umegaoka, Gōtokuji, Kyōdō, Chitose-Funabashi, Soshigaya-Ōkura, Seijōgakuen-Mae, Kitami Stations
• Tokyu Corporation
  • Den-en-toshi Line: Ikejiri Ohashi, Sangen-Jaya, Komazawa Daigaku, Sakura Shinmachi, Yōga, Futako-Tamagawa Stations
  • Meguro Line: Okusawa Station
  • Oimachi Line: Midorigaoka, (Jiyūgaoka), Kuhon-butsu, Oyamadai, Todoroki, Kaminoge, Futako-Tamagawa Stations
  • Setagaya Line (LRT): Sangen-Jaya, Nishi Taishido, Wakabayashi, Shoin Jinja-mae, Setagaya, Kami Machi, Miyanosaka, Yamashita, Matsubara, Shimo Takaido Stations
  • Toyoko Line: (Jiyūgaoka Station)

• Tōmei Expressway ( Asian Highway 1)
• Chūō Expressway
• Daisan Keihin Road
• Shuto Expressway
  • No. 3 Shibuya Route
  • No. 4 Shinjuku Route

• National Route 20 "Kōshū Kaidō"
• National Route 246 "Tamagawa Dōri"
• National Route 466

• Tokyo Metropolitan Road 3 "Setagaya Dōri"
• Tokyo Metropolitan Road 311 "Kanpachi Dōri"
• Tokyo Metropolitan Road 312 "Meguro Dōri"
• Tokyo Metropolitan Road 318 "Kan-nana Dōri"
• Tokyo Metropolitan Road 416 "Komazawa Dōri"

On April 25, 2011, amid national concern over the safety of nuclear power triggered by the March 11 earthquake and Fukushima I nuclear accidents, former Social Democratic Party House of Representatives legislator Nobuto Hosaka was elected mayor on an anti-nuclear platform. Prior to becoming mayor, Hosaka was also well known for his staunch opposition of the death penalty and his defense of Japan's Otaku culture.

• Rakuten has its headquarters building "Rakuten Crimson House" in Setagaya.
• Toho has studio facilities in Setagaya.
• OLM, Inc. has its studios in Setagaya.
• Ivan Ramen restaurant: a ramen shop owned by an American chef.

These are schools operated by agencies of the central Government of Japan.

The Tokyo Metropolitan Government Board of Education operates following senior high schools in Setagaya.

The Setagaya City Board of Education [ja] operates 29 junior high schools in Setagaya.

They are:

Former schools:

This section needs expansion. You can help by adding to it. (November 2022)

The Setagaya City Board of Education operates 61 elementary schools in Setagaya.

They are:

Former schools:

• Hanamido Elementary School (花見堂小学校)
• Higashi Ohara Elementary School (東大原小学校)
• Kitazawa Elementary School (北沢小学校)
• Moriyama Elementary School (守山小学校)

Former international schools:

• Tokyo No. 8 Korean Elementary School (東京朝鮮第八初級学校) – North Korean school

• Bunbury City in Australia (since 1992)
• Döbling District, Vienna City in Austria (since 1985)
• Winnipeg City in Canada (since 1970)

• Embassy of the Republic of Angola
• Embassy of the Republic of Cameroon
• Embassy of Mozambique
• Embassy of Rwanda
• Embassy of Tanzania
• Honorary Consulate-General of the Central African Republic in Tokyo
• Honorary Consulate-General of the Republic of Malta in Tokyo

• Shūichi Gonda, Professional football player
• Yasuo Fukuda, Politician, 91st Prime Minister
• Akiko Santō, Politician, 32nd President of the House of Councillors
• Fusako Shigenobu, Terrorist, leader of the Japanese Red Army
• Fighting Harada, World boxing champion
• Akiko Kojima, Miss Universe 1959
• Nobuyuki Idei, Former CEO of Sony
• Akihiko Hoshide, Astronaut
• Kuniko Mukōda, Screenwriter, Novelist, Essayist
• Kōki Mitani, Playwright, Screenwriter, Theatre director
• Shirō Sagisu, Composer
• Kiichi Nakai, Actor
• Yoshino Kimura, Actress
• Eiko Koike, Actress
• Sayaka Kanda, Singer, Actress
• Naoto Arai, Professional football player
• Kaz Hayashi, Professional wrestler
• Shota Umino, Professional wrestler
• Hideo Kojima, Video game designer best known as the creator of the Metal Gear franchise
• Satoshi Tajiri, Video game designer and director best known as the creator of the Pokémon media franchise
• Noritake Kinashi, Comedian, actor, singer, artist and J-Pop idol, member of comedy duo Tunnels and former member of J-pop group Yaen
• Yoshinori Muto, International footballer
• Mika Kanai, Voice actress
• Rei Sakuma, Voice actress
• Shino Kakinuma, Voice actress
• Ichirou Mizuki, Singer, voice actor
• Yuki Kunii, Motorcycle racer
• Mariko Kawana, Porn actress, erotic novelist, human rights activist
• Matt Kuwata, Model, musician, media personality
• Keigo Oyamada, Singer

• Setagaya family murder

• Setagaya City Official Website (in Japanese)