The planar Hall effect has been described by theoretical analyses, and previous investigators have shown that the observed effect is consistent with these predictions. However, the amount of experimental data reported to date is small, and the work described herein provides additional data concerning the planar Hall effect in both polycrystalline and single‐crystal thin films. The calculations of the planar Hall coefficient and of the magnetoresistance factor based on these data show close agreement with the data obtained by other investigators. It is also apparent that, as has been predicted from theory, the influence of the crystalline symmetry is not dominant in the effect in ferromagnetic films at room temperature. The observations also indicate that the planar Hall effect may be potentially useful in electronic‐device applications.