The purpose of this case study research was to explore the effects of explicit instruction of graphic organizers to support students' understandings of informational text. An additional purpose was to investigate students' perceptions of using graphic organizers as a comprehension strategy. Using case study methodology, this study occurred during 6 weeks of instruction in a third-grade classroom in a suburban school outside a large metropolitan area. The teacher-as-researcher applied purposeful sampling to obtain 6 students. Over the course of the study, the teacher-as-researcher provided daily 45-minute literacy lessons including social studies content, reading comprehension strategies, think-aloud strategies, and teacher modeling of compare/contrast graphic organizers. After whole-class lessons, students worked independently or in small groups to learn content and to practice using reading strategies and think-alouds. For each of the 6 case studies, researchers collected and analyzed the following: (a) student work samples, including graphic organizers, (b) students' responses to open-ended interviews probing about graphic organizers as a comprehension strategy, (c) student reflective journals, and (d) think-aloud protocols. Data were interpreted in a manner to illustrate both a "big picture" (macrostructure) and a critical analysis of individual students (microstructure). The major findings of the present study were that students seem to find graphic organizers useful, that they are able to independently use them, that they face some obstacles using them, and that they learn new concepts about informational text as a result of using graphic organizers. The case study students reported that the graphic organizers helped them to determine important information in the text. Furthermore, students pointed to graphic organizers as providing instructional strategies that assisted them in becoming diligent and purposeful readers. Thus, this research adds to the body of growing evidence showing the instructional benefits of graphic organizers as a means to scaffold and support students' understandings of informational text. As such, this study extends the promising findings about the use of graphic organizers from middle schools and high schools to the elementary level. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]