The determinants of collective behavior were studied in a laboratory setting. Subjects were members of a disadvantaged group. In a 3 x 2 factorial design two independent variables were manipulated. The magnitude of pay inequality between the disadvantaged group and a more advantaged group was manipulated to be large, moderate, or small. Mobilization resources available to the disadvantaged group were manipulated to be either present or absent. In accord with predictions based on relative deprivation (RD) theory, as the magnitude of the inequality increased, stronger feelings of deprivation were expressed. However, contrary to RD theory, larger magnitudes of inequality and stronger feelings of deprivation were not associated with greater willingness to engage in legitimate or illegitimate forms of collective behavior. Instead, as predicted by some critics of RD theory, willingness to engage in illegitimate forms of collective behavior was affected only by the presence or absence of mobilization resources. These findings are integrated with the mixed results of previous research conducted by both proponents and critics of RD theory. Two interpretations are offered. The first suggests severe reductions in the scope of the RD explanation for collective behavior and the second suggests that in this domain of psychological research, as in others, emotional attitudes may be loosely coupled with behavior.