A screw-less fixing assembly for an interface card having a fixing support includes a frame, a movable cover module and an elastic member. The frame has an I/O opening. One side of the I/O opening is provided with an accommodating space. A long plate of the fixing support is positioned to correspond to the I/O opening, and a short plate of the fixing support is received in the accommodating space. The movable cover module is mounted in the accommodating space. The elastic member has an elastic protrusion positioned to correspond to the short plate of the fixing support. The movable cover module is moved to drive the elastic protrusion to tightly fix the short plate of the fixing support to the frame. With this arrangement, the interface card can be rapidly detached from the frame or attached thereto without using screws.