The effect of additions of up to 1 mol% Al2O3 on abnormal grain growth in BaTiO3 has been studied. For samples sintered at temperatures <= 1250 degrees C addition of 0.1 mol% Al2O3 increases the number density of abnormal grains, with further additions reducing the number density. For samples sintered at 1350 degrees C, addition of Al2O3 caused the primary abnormal grain size to decrease and then increase. The results are explained by considering the effect of Al2O3 addition on the TiO2 content of grain boundaries. (c) 2005 Elsevier Ltd. All rights reserved.