An air conditioner may include a compressor that compresses refrigerant; a condenser that condenses the refrigerant; at least one expansion valve that expands the refrigerant; a gas-liquid separator that separates and discharges the refrigerant into gas refrigerant and liquid refrigerant; an evaporator that evaporates the liquid refrigerant discharged from the gas-liquid separator; a refrigerant inflow pipe that connects the expansion valve and the gas-liquid separator; a bypass pipe that connects the gas-liquid separator and the compressor; and a refrigerant discharge pipe that connects the gas-liquid separator and the evaporator. The gas-liquid separator may include a housing in which a portion of the refrigerant inflow pipe, the bypass pipe, and the refrigerant discharge pipe may be disposed, and first and second partition walls disposed in the housing.