A modular cosmetic system for storing cosmetic items in an organized fashion. In particular, a device and system that is configured to interchangeably fit modular boxes. Each modular box can be removably arranged inside the trays, permitting a user to customize the structure of their cosmetic system. The modular cosmetic system includes nine different sized modular boxes for holding different products. This allows for the creation of a unique, adjustable box to store a variety of different makeup products and the like.