This What Works Clearinghouse (WWC) intervention report summarizes the research on the effectiveness of Reading Apprenticeship®, a professional development program that aims to help teachers improve student literacy skills in core academic subjects, including English, mathematics, science, and social studies. Reading Apprenticeship® trains teachers to model reading comprehension strategies and help students practice these strategies. Based on five studies that meet WWC standards, the WWC found moderate evidence that Reading Apprenticeship® positively impacted student science achievement and overall grade point average, compared with students whose teachers did not receive Reading Apprenticeship® professional development. The WWC found uncertain effects on student achievement in life sciences, social studies, literacy, reading comprehension, vocabulary, and mathematics.