A compact and wide-stopband filtering power divider (FPD) based on a single shielded circular patch resonator (SCPR) is presented in this paper. The SCPR is first introduced, which consists of a circular patch resonator loaded with a center metal via and a ring of shielding metal vias. When the TM mode resonates, the half-mode SCPR (HMSCPR) and the quarter-mode SCPR (QMSCPR) obtained by dividing the full-mode SCPR (FMSCPR) with multiple slots have the same resonant frequency. Notedly, as the size of the resonator decreases, some higher-order modes are correspondingly suppressed. By combining an HMSCPR and two QMSCPRs, a compact second-order FPD with improved stopband performance can be realized. The good isolation between output ports can be achieved by loading three isolation resistors at the slots of two adjacent QMSCPRs. A prototype is designed, simulated, and measured to verify the proposed method.