In this paper, we present an orientation sensor based on the chipless RFID technology. The approach is justified analytically and permits to estimate the angle in a range of 90° from the measured S-parameters in cross-polarization using both magnitude and phase of the backscattered signal. Simulations and measurements are performed to evaluate the performance of the proposed approach. Results show that the orientation can be recovered in real environment with an error of 3° and 5° at a distance of 10 cm and 20 cm, respectively.