A toughening concept for glass, based on exploiting the ferroelastic effect of piezoelectric particles embedded in a glass matrix, is described. It is hypothesized that the domains within a piezoelectric phase will align themselves in the direction of the stress field around an advancing crack, thus absorbing energy and contributing to toughening. A powder technology route was optimized to fabricate lead-containing glass-matrix composites with up to 30 wt% of a lead zirconate titanate (PZT) particulate phase. An increase in fracture toughness of >50% was achieved via the addition of 30 wt% of PZT particles. Although other toughening mechanisms could be excluded in the present composites, the actual contribution of piezoelectric toughening remains under investigation.