The equity rule is favored by groups that emphasize productivity, but there is limited support for the notion that equity actually facilitates productivity in groups (Deutsch, 1985). We propose that the relationship between equity and productivity may depend on whether individual group members have an independent or interdependent self-construal. This prediction was tested in an experiment in which groups endorsed either an equity rule or an equality rule for distributing resources and then generated ideas as a group. The results showed that equity facilitated productivity (e.g., the number of ideas generated) but only in groups whose members had been primed with an independent self-construal. The results of both self-report and video-tape data support competition as the mechanism that explains this productivity gain. This work contributes to research on both distributive justice and small group performance by specifying more clearly the conditions under which a belief in equity will stimulate productivity.