The just world hypothesis states that people have a need to believe that their environment is a just and orderly place where people usually get what they deserve. The present article reviews the experimental research that has been generated by the just world hypothesis. Considerable attention is devoted to an experiment by M. J. Lerner and C. H. Simmons (see record 1966-11086-001). In light of the existing empirical findings, an elaboration of the initial hypothesis is offered, and it is suggested that people’s need to believe in a just world affects their reaction to the innocent suffering of others. Finally, recurrent conceptual misinterpretations and methodological errors found in the literature are identified.