A capacitive coupling based proximity sensor is disclosed. In some embodiments, a sensor embedded in a mobile device comprises a transmitter configured to transmit a transmit signal and a receiver configured to receive a receive signal via capacitive coupling between the receiver and the transmitter as well as a circuit configured to detect human proximity to the mobile device in the event that the receive signal does not sufficiently match the transmit signal and configured to generate an output signal indicating human proximity to the mobile device that is employed to facilitate an appropriate response.