In this paper, we provide a research synthesis of single-case studies on the efficacy of graphic organizers to improve the writing composition outcomes of students with learning disabilities in grades K-12. A series of electronic searches, a hand search, and an ancestral search were conducted to locate relevant articles from 1975 to July 2017. Ten studies, including nine peer-reviewed articles and one doctoral dissertation, were retrieved that met our established criteria for inclusion. Findings indicated that graphic organizers were predominantly effective in improving the narrative and expository essay writing skills of students with learning disabilities. A discussion of the studies along with limitations and suggestions for future graphic organizer intervention research are presented.