Abstarct: In this paper, both direct and indirect adaptive fuzzy backstepping control is provided for a ball and beam system utilizing output feedback. Firstly, a nonlinear velocity observer is designed for the system and then adaptive fuzzy backstepping control is accomplished by the system states estimate. A fuzzy system with adaptive mechanism should be used to estimate the dynamics of the system because modeling physical systems is always associated with uncertainty and also backstepping controller requires dynamic information system. For this reason, in the following, direct and indirect adaptive fuzzy backstepping controller is provided for the ball and beam system. The observer and control system stability are shown by the Lyapunov theory. Simulation results illustrate the proper functioning of the observer and also adaptive fuzzy backstepping control method on the ball and beam system. Also, the results of the proposed method are compared with an existing method in order to show the performance and accuracy of the controller.