Embodiments of the present disclosure provide self-calibrated thermal sensors of an integrated circuit (IC) die and associated techniques and configurations. In one embodiment, a self-calibrating thermal sensing device includes a resonator configured to oscillate at a frequency corresponding with a temperature of circuitry of an integrated circuit (IC) die, wherein the resonator is thermally coupled with the circuitry and configured to operate in a first mode and a second mode and logic operatively coupled with the resonator, and configured to calculate a first temperature corresponding with a first frequency of the resonator in the first mode using a first equation, calculate a second temperature corresponding with a second frequency of the resonator in the second mode using a second equation, and add an offset to the first equation and the second equation based on a result of a comparison of the first temperature and the second temperature. Other embodiments may be described and/or claimed.