A combined ventilation and microwave oven system includes an external enclosure with a top portion defining recirculation vent outlets, a cooling air outlet, and an outside vent outlet, side portions, and a bottom portion defining vent inlets. The vent inlets are in fluid communication with the recirculation vent outlets in a recirculation mode and the outside vent outlet in an outside vent mode. A cooling fan is disposed between the cooking cavity and the first side portion and is configured to direct air through the cooling air inlet and the cooling air outlet. A hood assembly is disposed within the external enclosure and includes at least one first hood fan disposed between the cooking cavity and the first side portion, and a second hood fan disposed between the cooking cavity and the second side portion to direct air through the vent inlets and through an interior of the external enclosure.