This chapter discusses the conceptual framework underlying the PISA 2009 assessment of students’ reading competencies. It provides PISA’s definition of reading literacy and presents the elements of the survey which have remained consistent throughout the previous cycles, along with a new element: reading and understanding electronic texts. It describes how PISA assesses and analyses electronic reading tasks, as well as the way in which students navigate through texts and respond to the format of tasks. Sample print and electronic reading items are included throughout the chapter to further illustrate how students’ skill are measured. Finally, a discussion on reading engagement and metacognition addresses the motivational and behavioural elements of reading literacy.