The enthalpies of formation of the lanthanide trichlorides, tribromides and tri-iodides have been evaluated from the experimental data available in literature. All experimental results have been re-calculated using a consistent set of the most recent auxiliary data. On the basis of the results obtained, recommended values are given in those cases where sufficient data are available. When this is not the case, the recommended values are obtained from estimations using empirical correlations based on the variation of the ionic radii or the atomic number,