We report, for the first time, the realization of an integrated optic RF spectrum analyzer (IOSA) that combines a wideband acoustooptic Bragg cell and a pair of ion-milled waveguide lenses in ZnO/GaAs/Al0.15Ga0.85As composite waveguide 7 x 23 mm2 in size. A total of 10 and 40 channels at the center frequencies of 167 and 500 MHz, respectively, and a frequency resolution of 5.5 MHz have been accomplished. The diffraction efficiencies of 11.5 and 4.0% per watt of RF drive power at the center frequencies of 167 and 500 MHz, respectively, and a dynamic range larger than 16 dB was measured. Further integration of this IOSA with a laser source, a photodetector array, and electronic driving circuits could produce a monolithically integrated optic RF spectrum analyzer.