The magnetic circular dichroism-optically detected magnetic resonance (MCD-ODMR) spectrum of the 3d5 spin 5/2, configuration of Fe3+ at cubic sites has been observed in iron-doped indium phosphide. Microwave induced changes of the MCD signal near 1.27 eV (about 0.98 µm) are used to investigate the allowed, fine structure lines resulting from ?M=1 transitions in a strong magnetic field. In addition, the forbidden transitions between states for which ?M>1 have been identified in the weak field region. The spin Hamiltonian parameters describing this spectrum are g=2.022±0.001 and a=222±1×10-4 cm-1 and the inhomogeneously broadened line is approximately 12 mT wide. The MCD of iron in InP is attributed to an internal crystal field transition of cubic Fe3+ ions occupying In sublattice sites.