An implementation into the ADF program of a method for calculating zero-field splitting (ZFS) of molecules with spin degenerate ground states and S>1/2 is reported. ZFS can influence temperature-dependent magnetic circular dichroism (MCD) intensity. Previously published equations for the calculation of MCD with time-dependent density functional theory are modified to take zero-field splitting into account. The MCD spectra of the group 15 hydrides and the complex formed from iron (III), ethylenediaminetetraacetate and peroxide, [Fe(III)(EDTA)O2]3− are simulated. These spectra are analyzed with particular reference to the influence of ZFS on the MCD intensity.