A novel ultrawideband (UWB) ring-cavity multiple-way parallel power divider is presented in this paper. The approximated equivalent-circuit model of the power-dividing unit is presented to analyze its structural parameters and electrical performance. The overall circuit model of the proposed power divider is also given. To verify its potential to accommodate large numbers of power-dividing ports, a UWB 32-way ring-cavity power divider is developed with reasonable agreement between the simulated and measured results. The measured return loss is greater than 10 dB over the entire UWB and also greater than 15 dB from 4.2 to 9.2 GHz. The average insertion loss, amplitude imbalance, phase imbalance, and group delay are around 15.4 dB (including the 15-dB power-dividing insertion loss), $\pm$0.7 dB, $\pm 5^{\circ}$ , and 0.85 ns, respectively, across the UWB. In addition, the isolations between the output ports are greater than 10 dB over the UWB except for those between the adjacent output ports.