The review begins with a consideration of the dimensions of decisionmaking in the legal context and how decisionmaking may be evaluated. It then provides an overview of the principal theoretical approaches to the social psychology of decisionmaking. Most of the article is a review of specific areas of research: reliability of decisions, jury size and decision rules, jury selection, testing rules of evidence and procedure, expert and eye witnesses, quantitative and probabilistic evidence, detection of witness deception, decisionmaking by judges, instructions from the bench, and parole decisionmaking. The article concludes that social psychologists have mostly been concerned with the ability of individual decisionmakers and social decisionmaking entities to transform certain kinds of information into outcomes and with measuring the reliability and validity of those outcomes. The research has largely neglected the consequences of actual and possible variations in the structure of legal decisionmaking unrelated to outcomes. Other research shortcomings are the tendency not to view the legal system as a system and its obsession with procedural and evidentiary rules and practices. 93 references. (Author abstract modified)