Shipping and storage systems convertible between containers and racks are provided. Collapsible shipping and storage systems are provided, which include pallets with novel locking mechanisms. An embodiment includes a first pallet having an interface fitting and a locking component, a second pallet having a second interface fitting and a second locking component, and structural support members positionable between the pallets for supporting one of the pallets in spaced relation over the other pallet. The structural support members may include frame members and walls interchangeable with one another. The frame members may be combined with the pallets to establish a rack system having an open storage area. The walls also may be combined with the pallets to establish a storage container having a compartment.