M. J. Lerner (1980) proposed that people need to believe in a just world; thus, evidence that the world is not just is threatening, and people have a number of strategies for reducing such threats. Early research on this idea, and on just-world theory more broadly, was reviewed in early publications (e.g., M. J. Lerner, 1980; M. J. Lerner & D. T. Miller, 1978). In the present article, focus is directed on the post-1980 experimental research on this theory. First, 2 conceptualizations of the term belief in a just world are described, the typical experimental paradigms are explained, and a general overview of the post-1980 experiments is provided. Second, problems with this literature are discussed, including the unsystematic nature of the research. Third, important developments that have occurred, despite the problems reviewed, are described. Finally, theoretical challenges that researchers should address if this area of inquiry is to advance in the future are discussed.