Tachikawa (written: 立川) is a Japanese surname. Notable people with the surname include:
Akira Tachikawa, Japanese opera singer
Keiji Tachikawa (立川 敬二; born 1939), Japanese businessman and president of the Japan Aerospace Exploration Agency
Kotaro Tachikawa (立川 小太郎; born 1997), Japanese footballer
Kyouichi Tachikawa (立川 京一; born 1966), Japanese historian
Megumi Tachikawa (立川 恵), Japanese manga artist
Sae Tachikawa (立川 サエ; 1889–1990), Japanese-American educator
Tachikawa Sumito (立川清登; 1929–1985), Japanese operatic baritone, radio host, and television personality
Takashi Tachikawa (立川 隆史; born 1975), Japanese baseball player
Yuzuru Tachikawa (立川 譲; born 1981), Japanese director
Fictional characters
Mimi Tachikawa (太刀川 ミミ), a character in the anime series Digimon Adventure