Koga is a Japanese surname. Notable people with the surname include:
Harue Koga, Japanese painter active in the Taishō period
Hiroyasu Koga, Yukio Mishima's kaishakunin
Issei Koga, for Democratic Party of Japan
Junya Koga, Japanese swimmer
Kazunari Koga, Japanese footballer
Makoto Koga, Japanese Liberal Democratic Party politician
Mary Koga (1920-2001), Japanese-American photographer and social worker in Chicago
Masahiro Koga, Japanese footballer
Masao Koga, was a Japanese composer, guitarist and pop musician
Mineichi Koga (1885–1944), Fleet Admiral during World War II
Mitsuki Koga, actor in martial arts films
Satoshi Koga, Japanese footballer
Seiji Koga, Japanese footballer
Tadayoshi Koga, pilot of the Akutan Zero in World War II
Takuma Koga, Japanese footballer
Toshihiko Koga, a judo world champion
Yun Kōga (born 1965), Japanese manga artist
Sebastian Marius Flaminius Koga (born 1977), Romanian-American neurosurgeon
