Modeling of an Ultrasonic Rotary Motor covers a review of different types of ultrasonic motors such as linear and rotary types, and a brief review of control techniques used for applying these new type of actuators in fields like robotics, medicine, micro-positioning and the automotive industry. Owing to the operating principle of the ultrasonic motor uses high-frequency oscillations to convert these oscillations of small amplitude in low speed rotations of a shaft, the mathematical model of ultrasonic motors includes the study of the piezoelectric effect, the generation of traveling waves in a continuous medium, the friction phenomenon, including the Stribeck effect and the stick-slip phenomenon, and finally the dynamics of a rotary system. The model includes the characterization of the torque-speed hysteresis, which was validated through experimental data. In addition, the role of model parameters into the hysteresis characterization was studied in detail. The present study provides an insight of the nature of ultrasonic rotary motors and it is a valuable resource to the scientific community.