A fastener for a socket connector includes a frame and a pressing assembly. The frame has an opening and a plurality of protrusions. The protrusions extend from inner edges of the frame toward the opening. The pressing assembly has a cover and a buckling piece. The cover is pivotally connected to the frame. The buckling piece locks the cover on the frame. Using the above arrangement, the protrusions are used to accurately align the socket connector within the opening, thus the inter edge surface of the frame is aligned with the outer peripheral surface of the socket connector. In this way, the pressing assembly of the frame can be operated accurately to lock and press a chip module on the socket connector.