A differentially controlled variable capacitor includes two variable capacitors that are arranged effectively in parallel and receive differential input. The variable capacitors are coupled to a common node that is biased to a potential. For diode-type variable capacitors, the bias potential should ensure that the variable capacitors continue to operate as capacitors by preventing the diode device from becoming forward-biased. The differentially controlled variable capacitors are useful as tuning elements in circuits that require frequency control. A noise signal may be injected into the control signal of the variable capacitors. The effective parallel arrangement of the variable capacitors allows differential control of the effective capacitance value such that the noise signal does not alter the effective capacitance value. The differentially controlled variable capacitor is useful in circuits such as oscillators, tuned filters, and other electronic circuits that require a tuned frequency or tuned capacitance.