A developer supply container includes a container body, a developer conveyance member, and a clog prevention member. The container body includes an outlet port and contains developer therein. The developer conveyance member includes a rotational shaft and a conveyance-member body. The conveyance-member body is supported by the rotational shaft and has flexibility. The developer conveyance member is disposed in the container body and conveys the developer to the outlet port for discharge. The clog prevention member is formed in the conveyance-member body in a position corresponding to the outlet port. The clog prevention member goes into the outlet port to protrude to outside of the container body as the rotational shaft rotates.