Triple dielectric and magnetic resonance behaviors have been observed and studied in Co microflowers within a frequency range of 0.1–18.0 GHz. To characterize such triple‐resonance behaviors, the dielectric resonance was resolved by fitting the Lorentzian dispersion law, magnetic resonance spectra was fitted by the Landau–Lifshitz–Gilbert equation. It is demonstrated that our fitted and calculated resonance frequencies agree well with the experimental data. Dielectric resonance in permittivity was due to the dipole polarization. Magnetic resonance in permeability was due to the natural/exchange resonance. Both the permittivity and permeability determined and contributed to the microwave reflection loss.