Abstract: A modular container system may enable a user to create a set of interconnected containers to organize and pack small items. The modular container system may be assembled in various ways to hold one or more items in separate compartments of varying size. The modular container system may have the same diameter as a typical sports water bottle, making the container system easy to pack and readily accessible to the user. The modular container system may be useful in various situations where a person needs to organize and store items. Applications may include outdoor sports and recreation, military, automotive, arts and crafts, construction tools and materials, food storage, toy storage, and the like.