Junsaku Koizumi (小泉 淳作, Koizumi Junsaku, 1924 – 9 January 2012) was a Japanese painter and pottery artist.
In 1952, he graduated from Tokyo National University of Fine Arts and Music (present name Tokyo University of the Arts; Jap.
東京芸術大学 Tōkyō Geijutsu Daigaku or Geidai 芸大).
He held a number of gallery shows in Japan, and painted remarkable images on the ceilings of the Kennin-ji temple in Kyoto (2002), and Kenchō-ji temple in Kamakura (2003).
His ink paintings (suibokuga) of Japan's mountains have received critical acclaim.