Limited reliability of ferroelectric-based actuators restricts their use in high-performance applications, where stress-induced cracking of ferroelectric ceramics often leads to fatal failure. The main limiting factors are the relatively small fracture toughness and the brittle nature of ferroelectrics. However, ferroelectrics naturally exhibit fracture toughening (so called ferroelastic toughening) due to stress induced reorientation of non-180 degrees domains that inhibits crack propagation. Here we present a phase-field study of ferroelastic toughening based on Landau-Ginzburg-Devonshire theory. The primary qualitative factors that control the magnitude of ferroelastic toughening are identified and discussed. (c) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.