An electrical connector assembly includes a first connector. The first connector has a main body. The main body has a first end wall and a second end wall opposite to each other. Multiple first terminals are provided on the main body. The first connector is used to be mated with a circuit board. The circuit board has multiple first conductive portions, multiple second conductive portions and multiple first wires electrically connecting the first conductive portions and the second conductive portions correspondingly. The second conductive portion is correspondingly electrically connected to the first terminal. The first end wall is located closer to the first conductive portion relative to the second end wall. A top surface of the first end wall is lower than a corresponding first conductive portion adjacent to the first end wall.