Boron diffusivity in single‐crystal diamond has been investigated. To this aim, a novel method using impedance spectroscopy for the study of the atomic diffusivity in wide‐gap semiconductor has been developed, along with a model for the analysis of the dielectric response function. The advantages of this procedure are discussed. Boron diffusivity in diamond has been determined to be 6.9×10−20cm2 s−1at 800 °C. A discussion of the results and a comparison with previous estimates are presented.