AUGUST is the name of a Japanese developer of visual novels, known for creating the original work that served as the basis for the anime and manga series Tsuki wa Higashi ni Hi wa Nishi ni - Operation Sanctuary. The company developed and released the original visual novel game for Windows on September 26, 2003. This original game was an adult-oriented恋爱冒险游戏, utilizing the NScripter engine.

The original work by AUGUST was adapted into several other media formats. An anime television series based on AUGUST's work was produced by the studio RADIX and aired in Japan from June to September 2004. A manga adaptation, illustrated by Mika Takeda, was also published by ASCII Media Works. In addition, the game spawned multiple light novel adaptations and drama CDs.

The original visual novel was later ported to the Dreamcast and PlayStation 2 consoles by the company Alchemist in 2004, with these versions removing the adult content from the original PC release. The key staff for AUGUST's original game included るね as the director, 榊原拓, 内田ヒロユキ, and 安西秀明 as the writers, and べっかんこう as the artist responsible for the character designs. The anime adaptation retained the character designs originally conceived by べっかんこう for AUGUST's game.