An air conditioner may include a compressor that compresses a refrigerant; a condenser that condenses the refrigerant discharged from the compressor; at least one expansion valve that expands the refrigerant passed through the condenser; at least one gas-liquid separation pipe through which the refrigerant passed through the at least one expansion valve flows; a gas-liquid separator, into which the refrigerant passed through the at least one gas-liquid separation pipe is introduced, that separates and discharges the refrigerant introduced into the gas-liquid separator into gas refrigerant and liquid refrigerant; and an evaporator that evaporates the liquid refrigerant discharged from the gas-liquid separator. The gas refrigerant discharged from the gas-liquid separator and the refrigerant passed through the evaporator may be provided to the compressor.