Some demonstrative embodiments include devices, systems and/or methods of detecting transmitter power. For example, a device may include a power detection circuit, coupled by a first coupler to a transmit chain, to provide a first output representing a measured non-calibrated transmission power over the transmit chain; a reference circuit, coupled to a reference voltage by a second coupler, to provide a second output representing a measured reference coupling factor; and a calibrator to determine a calibrated transmission power over the transmit chain based on the first and second outputs.