The second-order elastic constants of AgBr have been measured from 20[ddot]C to 400[ddot]C. Over this range, C'11decreased by 50%, C’ decreased by 86%, C44decreased by 23%, C11decreased by 61%, C12decreased by 43%, and Bsdecreased by 51%. The decreases in the elastic constants are linear, as expected, until approximately 200[ddot]C, whereupon they all begin to decrease more rapidly than linearly. The variations from linearity range from 4% to 31% at 400[ddot]C. This anomalous behaviour near the melting point is similar to other silver halide physical properties and may be attributed to the unusually high defect concentration. Similar elastic constant changes are seen in superionic conductors near the superionic transition, indicating that the silver halides may be starting the transition to a superionic state when the halide sublattice melts and the transition is frustrated.