A temperature sensor, a processor including the same, and a method of operating the same are provided. The temperature sensor includes: a reference circuit configured to receive a supply voltage provided from outside the processor and utilized by a logic block of the processor for operation of the logic block, and generate, using the supply voltage, at least one temperature information signal that varies according to a temperature of the logic block and at least one reference signal that is substantially constant relative to the temperature of the logic block; and a digital temperature generator configured to receive the at least one temperature information signal and the at least one reference signal generated by the reference circuit, and generate a digital temperature information signal indicative of the temperature of the logic block based on the at least one temperature information signal and the at least one reference signal.