The effects of displacement currents on ferromagnetic resonance are investigated for perfectly insulating slabs magnetized normal to their surfaces. The surface spins are assumed to be free. It is found that, at constant frequency, the usual ferromagnetic resonance shifts to higher fields. Also, for sufficiently thick samples, new resonances may be excited on the low‐field side of the main resonances. For thinner samples, these additional resonances may not be resolved from the main resonance, but may contribute significantly to its intrinsic linewidth.