A developing cartridge is detachably mountable to a main assembly of an image forming apparatus by passing through a mounting guide provided in the main assembly. The developing cartridge includes a frame; a developer carrying member for carrying a developer for developing an electrostatic latent image; a portion to be guided for being guided by the mounting guide when the developing cartridge passes through the mounting guide; an accommodating portion for accommodating the developer; a seal member for unsealably sealing an opening for permitting supply of the developer from the accommodating portion to the developer carrying member; and a grip member, provided at a longitudinal end portion of the seal member, including a fixed portion dismountably fixed on the frame and a grip portion to be gripped when the seal member is removed. The grip portion is disposed in a state in which the grip portion is bent relative to the fixed portion in a direction crossing a mounting direction of the developing cartridge. The grip portion prevents mounting of the developing cartridge by contacting a part of the image forming apparatus when the developing cartridge is mounted in the main assembly of the image forming apparatus.