A developer supply container detachably mountable to an image forming apparatus, the container includes a container body for accommodating the developer; drive connection member, provided substantially at a rotation center of the developer supply container, for driving engagement with a driving member provided in the image forming apparatus, wherein the drive connection member has a drive transmitting portion for transmitting a rotational force received from the driving member to the container body, wherein the drive transmitting portion is disposed so as to be idly rotatable for a sufficient time after start of rotation of the drive transmitting portion and before engagement with the container body.