An envelope tracking power amplifier is disclosed herein. The envelope tracking power amplifier includes a multi-mode bias modulator and a power amplifier. The multi-mode bias modulator generates an envelope-modulated bias voltage from the envelope signal of an radio frequency (RF) signal whose power is to be amplified by using a linear amplifier and a switching amplifier each having varying current driving capability in response to an operation mode control signal that determines any one of low-level mode and high-level mode. The power amplifier is biased in response to the envelope-modulated bias voltage, amplifies the RF signal, and outputs the amplified RF signal to an antenna.