A power amplifier circuit includes a first amplifier that amplifies a first RF signal and outputs a second RF signal, a second amplifier that amplifies the second RF signal and outputs a third RF signal, a bias circuit that supplies a bias current or voltage to the first or second amplifier, and a bias adjustment circuit that adjusts the bias current or voltage on the basis of the first RF signal, the second RF signal, or the third RF signal. The bias adjustment circuit includes a first diode having an anode to which a control signal indicating a signal based on the first, second, or third RF signal is inputted, and a cathode connected to a ground. The bias circuit includes a bias transistor that outputs the bias current or voltage on the basis of a voltage at the anode of the first diode.