New polarimetric observations of Jupiter at 15.4 and 6.65 GHz have been combined with previously published values to determine the microwave spectrum of the planet. All of the data have been normalized to a consistent scale that should be good to 7% on a relative and, hopefully, on an absolute scale. The compound emission has then been separated into its thermal and polarized nonthermal components. The results show that a considerable range of models for the atmosphere of Jupiter will match the spectrum of the thermal component.The most reasonable model probably has an effective temperature near 130°K. The non-thermal synchrotron emission from the Van Allen belts of Jupiter has a peak in its spectrum near 800 MHz and a discontinuity at higher frequencies that suggests two radiation belts surrounding the planet. The polarized fraction of this synchrotron emission reaches a peak of about 30% near a frequency of 3000 MHz but drops on either side of this frequency.