Proficient reading comprehension provides an academic advantage for 21st century learners. However, students at the upper elementary level face increasingly challenging texts that require use of metacomprehension skills. Yet, there is a lack of formal instruction that assists students in practicing these metacomprehension skills in classrooms. Social interdependence theory (Johnson & Johnson, 1989) suggests that increased competitive and cooperative social interactions between students may have an impact on the acquisition of complex cognitive skills, such as reading comprehension and metacomprehension. The purpose of the current study was to examine the effects of social interdependence on both students' metacomprehension and reading comprehension. The study employed an embedded concurrent mixed methods quasi-experimental design to obtain both quantitative and qualitative data from students. Students (N = 184) from fourth- and fifth-grade classrooms were assigned to one of four conditions varying in social interdependence: individual, competitive, cooperative, and intergroup competitive. A 2x2 factorial design was used to compare the effects of competitive and cooperative conditions on metacomprehension training. The training was conducted on eight short expository reading passages during class time and distributed over three school weeks. Findings from the study did not reveal any statistically significant differences between social conditions on students' reading outcomes. The data suggested that metacomprehension training had a positive impact on students' reading comprehension skills overall. Implications for this research suggest that future studies need to consider students' level of prior ability and motivation in their intervention designs. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]