Princess Soft is a Japanese company specializing in the publishing and development of visual novel video games. It has two sister brands: Primavera, which specializes in female oriented products, and Nine's Fox, which also releases ports of adult visual novels. None of the three brands have released any products since 2009 and the company seems defunct.

Initially it was a brand of Zero System, but was later transferred to Oaks Co., Ltd..

[Edited from Wikipedia]