A terminal fitting (10) has a rectangular tubular box (11) with an open rear end. A tab (12) extends forward from the box (11) and a crimping portion (14) is behind the box (11) for connection to a wire (30). The box (11) includes a base plate (15), two side plates (16) extending from opposite left and right sides of the base plate (15), and a supporting plate (17) extending from the side plates (16) substantially parallel to the base plate (15). The rear end of the supporting plate (17) defines a locking portion (18) to engage a locking lance (49). Only one restricting plate (22) extends from an extending end edge of a supporting plate (17) toward the base plate (15) substantially parallel to the side plates (16). A rear end (22R) of the restricting plate (22) is in the box (11) forward of the locking portion (18).