An outboard motor has an engine, an engine cover forming an engine compartment for holding the engine therein, a ventilation system with an outer outlet ventilation space through which air in the engine compartment flows to the outside of the engine compartment, and a generator. The ventilation system includes a case disposed in the engine compartment and forming an air discharge passage leading to the outer outlet ventilation space. A fan is placed in the air discharge passage to deliver air by pressure from the engine compartment to the outer outlet ventilation space. The air discharge passage has an inlet ventilation passage formed in an upper space in the engine compartment and opening upward. The engine compartment holding the engine therein can be efficiently ventilated, and ventilation air can effectively cool the engine and can effectively suppress temperature rise in the engine compartment.