Motorized thread tensioner for a sewing machine. In one example embodiment, a motorized thread tensioner for a sewing machine may include a first disk, a second disk, a spring, a shaft having threads on a distal end, a nut threaded onto the threads of the shaft, and an electric motor. The shaft may be through the first disk, the second disk, and the spring. The electric motor may be coupled to the nut and configured to rotate the nut in a first rotational direction and a second rotational direction that is opposite to the first rotational direction. The rotation of the nut in the first rotational direction may cause the shaft to travel toward the electric motor. The rotation of the nut in the second rotational direction may cause the shaft to travel away from the electric motor.