A breathing assistance system having active noise control may include a gas delivery system, a patient interface, a connection system, and a noise control system. The gas delivery system may supply breathing gas to a patient via the connection system and the patient interface. The noise control system may include a processor, a speaker, a reference signal source, and a feedback sensor. The processor may generate noise control signals to be output by the speaker for canceling noise caused by a noise source of the breathing assistance system. The reference signal source may communicate reference signals associated with the noise source. The feedback sensor may detect noise caused by the noise source and noise control signals output by the speaker, and communicate to the processor feedback noise signals based on the detected noise. The processor may generate the noise control signals based at least on the reference signals and the feedback noise signals.