In this systematic review of literature that spans 1975-2015, integrated reading and writing interventions for students with learning disabilities (LD) or students with academic difficulties were evaluated to understand the extant research, identify encouraging practices, and guide future research. Ten studies met inclusion criteria and each study was evaluated according to the relevant What Works Clearinghouse (WWC) design standards. Eight of the 10 investigations were conducted with students in grades 4-8. While only 4 of the 10 studies met WWC design with or without reservations, results from these studies are encouraging. Study findings suggest several areas for immediate future research relating to methodological and treatment variables and considerations for classroom instruction in order to respond to advanced expectations for the successful integration of reading and writing across subjects. In addition to employing stronger experimental designs and additional replications of encouraging studies, future research should explore the utility of integrated reading and writing interventions with secondary students with who have academic difficulties.