Stacked CMOS power amplifier (PA) and radio frequency (RF) coupler devices and related methods are disclosed. The stacked device includes a CMOS PA die configured to receive a transmit input signal and to output an amplified transmit signal, and a RF coupler device configured to receive the amplified transmit signal, to output an antenna transmit signal, and to output an RF signal proportional to the antenna transmit signal. The CMOS PA die and the RF coupler device are stacked on top of and electrically coupled to each other, and the CMOS PA die and the RF coupler device are combined within a single semiconductor package. In some embodiments, the RF coupler device is positioned on top of the CMOS PA die, and in other embodiments the CMOS PA die is positioned on top of the RF coupler device.