The International Computer and Information Literacy Study (ICILS) studied the extent to which young people have developed computer and information literacy (CIL) to support their capacity to participate in the digital age. Many countries recognize the importance that education in information and communication technologies (ICT) has for enabling citizens to develop the competencies needed to access information and participate in transactions using ICT (European Commission, 2006). ICILS systematically investigated differences in CIL outcomes across the participating countries and looked at how these countries provide CIL-related education. The study also explored differences within and across 21 countries with respect to the relationship between the outcomes of CIL education and student characteristics and school contexts. ICILS based its investigation on four research questions concerned with: (1) Variations in CIL between and within countries; (2) Aspects of schools, education systems, and teaching associated with student achievement in CIL; (3) The extent to which students' access to, familiarity with, and self-reported proficiency in using computers is associated with student achievement in CIL; and (4) The aspects of students' personal and social backgrounds that are associated with CIL. Following an overview, this report begins with three chapters that cover the instruments that were used in the study. Appreciation of the material in these chapters provides an essential foundation for interpreting the results of the study. Chapter 4 details the development of the questionnaires used in ICILS for gathering data from students, teachers, principals, and school ICT coordinators. The chapter also provides an outline of the development of the national contexts survey, completed by the national research coordinators (NRCs). Chapters 5 through 9 focus on the implementation of the survey in 2013. Chapters 10 through 13 are concerned with data management and analysis. [Contributors to this report include: John Ainley, Ralph Carstens, Diego Cortes, David Ebbs, Julian Fraillon, Tim Friedman, Eveline Gebhardt, Michael Jung, Paulína Koršnáková, Sabine Meinck, and Wolfram Schulz.]