An electrical connector assembly includes two electrical connectors locking to each other to form electrical connection. One of the electrical connectors provides a holding element having a press section and at least a latch protrusion with a contact baffle wall. The other is a mating electrical connector provides an locking groove to buckle with the latch protrusion and a lateral side of the locking groove and the contact baffle wall. Hence, the contact baffle wall will contact one lateral side of the locking groove steadily without the moment of force from the flexibility of the slit rib for increasing endurance of the operations of inserting and detaching with the lock of a mating electrical connector.