A microwave oven having a cooking chamber, at least one heat outlet provided in a sidewall of the cooking chamber, at least one heat inlet provided in the center of the sidewall of the cooking chamber, and a convection assembly. The convection assembly is disposed on an external side of the sidewall of the cooking chamber, and includes a fan, a heating element, and at least one guide bracket which guides heat from the heating element through the at least one heat outlet and into the cooking chamber. According to this configuration, a microwave oven heats food more evenly and efficiently.