A socket connector (1) includes an insulative housing (2) and a plurality of terminals (7) received in the housing. The housing defines a plurality of passageways (24) for accommodating the corresponding terminals. Each passageway forms a step (248) therein for dividing the passageway into a receiving channel (246) and an interfering channel (242). Each terminal defines a fastening portion (70) for securing the terminal in the passageway and the fastening portion forms a pair of straight interfering sides (710). The distance from one of two straight interfering sides to the other is greater than the width of the interfering channel. When the terminal is installed into the housing, the terminal is firmly positioned in corresponding passageway by virtue of the interfering force between the two straight interfering sides and the interfering channel.