An apparatus is disclosed for oscillator feedthrough calibration, such as a component arrangement that can be calibrated to account for signal leakage from an oscillator coupled to a mixer circuit. In example aspects, the apparatus includes a mixer circuit having a first stage, a second stage, and tuning circuitry. The first stage includes at least one transistor coupled between a mixer input and a mixer output. The second stage includes one or more transistors coupled between the at least one transistor of the first stage and the mixer output. The one or more transistors are also coupled between a local oscillator signal input and the mixer output. The tuning circuitry includes at least one current source coupled to the at least one transistor of the first stage.