A developer supply container includes a developer accommodating portion for accommodating a developer, a discharge opening for permitting discharging of the developer from the developer accommodating portion, a drive inputting portion for receiving a driving force, and a pump portion. The pump portion is driven by the driving force received by the drive inputting portion to alternate an internal pressure of the developer accommodating portion between a pressure lower than an ambient pressure and a pressure higher than the ambient pressure. In addition, a regulating portion regulates a position of the pump portion at a start of operation of the pump portion so that in an initial operational period of the pump portion, air is taken into the developer accommodating portion through the discharge opening, and a nozzle portion connected to the pump portion and has an opening at an end that is disposed adjacent to the discharge opening.