

Sister Princess is built around the idea that a regular young man (the player) is thrust into a home life with twelve charming little sisters, each possessing their own unique traits and personalities. The player has roughly a month to spend with the sisters, with each day divided into three time slots: the first is free time before noon, followed by a post-lunch period, and ending with the time before bed. During the day, the player can choose which girl, if any, to accompany to school. The afternoon segment mirrors the morning in structure but offers additional options, allowing the player to visit various locations in town or walk home with one of the sisters. Each night before sleep, the player can check and respond to e-mails. As the player continues to engage with the sisters, their attitudes toward their big brother will evolve, ultimately leading to one of the game’s endings. Each sister has two possible endings: the standard ending and the "non-blood relation" ending. As the name implies, the special ending reveals that the player character and the sister are not actually related by blood. In some cases, particularly with the older sisters, this can lead to a scenario where the protagonist and the "sister" end up getting married.
| PS1 | March 8, 2001 |
| DC | March 28, 2002 |