The slow shear acoustic wave attenuation in a tellurium dioxide crystal (11¯0) plane is examined. The measurements were carried out for two crystal cutoff angles: 7° and 10.5° from the [110] axis. The ultrasound attenuation was examined in the frequency range of 80 to 300 MHz by the acousto-optic (AO) method. The attenuation coefficients were determined for both acoustic wave propagation directions for the frequency range of 200 to 300 MHz. The influence of ultrasound attenuation on the AO cell transmission functions was examined for the 10.5° AO cell both theoretically and experimentally. It is shown that acoustic wave absorption affects mainly the AO diffraction efficiency. The attenuation influence on the AO cell transmission function shape and its half-width is not significant.