A process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The process cartridge includes a coupling member provided at an axial end portion of a photosensitive drum and rotatable about a coupling axis thereof so as to transmit a driving force to the photosensitive drum. The coupling member is capable of inclining relative to the photosensitive drum so that the coupling axis inclines relative to a drum axis, with the coupling member having a first end portion connected to the photosensitive drum, a second end portion, and a connecting portion between the first end portion and the second end portion. A maximum distance from the coupling axis to an outermost surface of the connecting portion along a line perpendicular to the coupling axis is less than a maximum distance from the coupling axis to an outermost surface of the second end portion along a line perpendicular to the coupling axis.