A developer container includes a container body, a lid, a movable wall, and a sealing member. The container body includes an inner circumferential surface defining a cylindrical internal space extending in a first direction, and a wall part defining one end surface of the internal space in the first direction. The container body has a developer discharge port closer to the wall part. The movable wall includes an outer circumferential surface and a conveying surface defining a storage space for the developer. The movable wall is movable in the internal space in the first direction from an initial position closer to the lid of the container body to a terminal position closer to the wall part while conveying the developer in the storage space. The wall part has a developer filling port penetrating the wall part and communicating with the storage space. The sealing member seals the developer filling port.