PISA for Development (PISA-D) is a six-year project set to conclude in 2019. From 2021, the initiative will be integrated into the main PISA test, making the assessment more accessible and relevant to a wider range of countries, especially middle- and low-income countries. The PISA 2021 cognitive instruments will use adaptive testing that allows for more items suitable for students with lower levels of proficiency, and the contextual questionnaires will be better suited to capture the diverse situations of students in lower-income countries. Support for capacity building, analysis and reporting will be offered as an option to all countries participating in PISA, and an optional module to incorporate out-of-school 15-year-olds in the assessment will also be offered.