This paper proposes a simple speed control method for dual interior permanent magnet synchronous motors fed by a single inverter. Two motors are connected in parallel with a single inverter. One motor is selected as the master motor, controlled by the inverter, and the other motor is selected as the slave motor, coupled to the master motor. Since both motors are controlled by a single inverter, applying a conventional speed control method for a single motor causes torque oscillation when the torque loads of the two motors differ. This causes a speed difference between the motors and destabilizes the system. Therefore, a dual motor drive system requires an additional control strategy. The proposed control method reduces the instability of the slave motor with a conventional proportional-integral speed controller. The performance of the proposed speed control method for a dual motor drive system is verified through simulations and experiments.