A technique is proposed for measuring the anisotropy energy of magneto‐optical media. the technique consists of rotating a sample in a fixed external magnetic field and monitoring the extraordinary Hall effect signal of the sample. From the Hall effect signal, the angle of rotation of the sample, and the saturation magnetization of the sample (which is measured separately by a vibrating sample magnetometer), we obtain the anisotropy energy as a function of the deviation of magnetization from the easy axis. The technique is applied to multilayered Co/Pd and Co/Pt films as well as to amorphous rare‐earth transition metal TbFeCo alloy films. The anisotropy constants thus obtained are compared with those obtained using other techniques such as torque magnetometry and Hall effect (or Kerr effect) measurements with applied field in the plane of the sample.