The possibility of turning fiber-reinforced aluminum alloy composites using a carbide tool was examined. Two types of short alumina fibers, which have the same fiber size, but a different chemical composition and hardness, were used as the reinforcements. The composites were fabricated by squeeze casting. Optical microscopy revealed that the fibers were randomly arranged in the alloy matrix. Fiber reinforcement decreased the cutting force and feed force of the aluminum alloy. The lower the hardness of the fiber in the composite, the lower the cutting force and feed force of the composite. The roughness of the machined surface was significantly decreased by the fiber reinforcement under every cutting condition. Observation of the chip formed on the machined surface indicated that the decrease in the surface roughness by the reinforcement was due to the suppression of the built-up-edge formation. Roughness values of the machined surface of the composite were similar to those when a diamond tool was used. The decrease in the hardness of the fibers in the composite had a significant effect on providing the long tool life.