Research is failing to consistently report theoretical frameworks, increasing the gap between research and practice, and increasing the difficulty teachers face in effectively matching interventions with student needs. However, this lack of theoretical understanding has not been well documented in the current literature. The purpose of this systematic review is to determine the literacy theories used in published articles within the "Journal of Adolescent and Adult Literacy" ("JAAL"). "JAAL" is a peer-reviewed literacy journal that focuses on providing research-based practices for teachers. The present study includes an overview of published theories of reading and writing and the results of coding for these theories within a sample of ninety-four published intervention articles. Through this review, we have uncovered several areas for future research: (1) clarification of the differences between sociocultural and sociocognitive theories, (2) an increased emphasis on the mutual impact of reading and writing, and (3) a need to diversify theories used for reading and writing instruction.