A connector for a circuit board includes a connector housing having a mounting arm. The mounting arm has a first fastening element that is releasably connectable to a first connecting element on the circuit board. The connection between the first fastening element and the first connecting element can be established and/or released by deflecting the mounting arm. A securing unit is disposed on the connector housing in such a way that the securing unit is movable between a releasing position and a locking position. In the locking position, the securing unit blocks deflection of the mounting arm. In the releasing position, the securing unit enables deflection of the mounting arm.