An optical connector adapter includes: a first connection member; a second connection member; a sleeve member coaxially disposed in the first and second connection members; an outer shell defining an internal cavity for receiving the first and second connection members, an engagement section being formed on an inner wall face of the internal cavity and inward protruding from the inner wall face for restricting and locating the first connection member, the outer shell being formed with at least one slot in communication with the cavity; and at least one U-shaped clamp member. The U-shaped clamp member can be inserted into the outer shell through the slot to restrict the second connection member so as to securely locate the first and second connection members in the outer shell.