This study investigated the efficiency of communication between children from different social-class backgrounds. Eight same-sex pairs of fifth graders—half boys and half girls—were formed into dyadic groupings by combining lower- and middle-SES children into the four possible speaker-listener combinations. Task success depended on the efficiency of the verbal communication between the pair. The listener was allowed to give feedback in one condition and not allowed to speak in the other condition. Significant SES-combination effects in communication efficiency were typically not found. Unexpected sex main effects showed general superiority of the girls in both conditions. The results suggest that lower-SES children's relative ability to communicate is highly dependent on the nature of the task.