Atomistic computer modelling and Extended X-ray Absorption Fine Structure (EXAFS) measurements were used in a study of the mode of solution of Sr2+ions in La2O3. The results are in agreement with previous modeling studies which show that the most favourable mode of solution is cation substitution with anion vacancy charge compensation. The energy of solution was found to be 1.3 eV. The Sr K-edge EXAFS results for 10 and 20 mole percent Sr2+doped La2O3were consistent with cation substitution. For both doped samples the EXAFS indicate the presence of a defect cluster containing 2SrLaions adjacent to a Vo.