REL Appalachia conducted a systematic review of the research evidence on the effects of increased learning time. After screening more than 7,000 studies, REL Appalachia identified 30 that met the most rigorous standards for research. A review of those 30 studies found that increased learning time does not always produce positive results. However, some forms of instruction tailored to the needs of specific types of students were found to improve their circumstances. Specific findings include: (1) Increased learning time promoted student achievement in mathematics and literacy when instruction was led by a certified teacher and when teachers used a traditional instructional style (i.e., the teacher is responsible for the progression of activities and students follow directions to complete tasks); (2) Increased learning time improved literacy outcomes for students performing below standards; and (3) Increased learning time improved social-emotional skills of students with attention deficit/hyperactivity disorder. Four appendices present: (1) Research methodology; (2) Program descriptions of the 30 reviewed studies; (3) Program implementation in the reviewed studies; and (4) Narrative summaries of the increased learning time programs evaluated in the studies reviewed. [This report was prepared for the Institute of Education Sciences (IES) by Regional Educational Laboratory Appalachia administered by CNA.]