The IEA International Computer and Information Literacy Study (ICILS) Teacher Panel is an international comparative study that investigates changes in the use of information and communication technology (ICT) in schools before and during the global pandemic. The ICILS Teacher Panel marks the first time in 40 years that IEA has conducted a panel study and collected longitudinal data. Building on ICILS as the baseline, the panel study collected longitudinal data on computers and technology use in education from school principals, ICT-coordinators, and teachers, in Denmark, Finland, and Uruguay. The ICILS Teacher Panel explores differences among and within countries in the changes of ICT-related resourcing within schools and responses to issues such as, respondents' attitudes towards technology, the use of ICT in teaching and learning, and whether social inequality in educational opportunity increased during the COVID-19 pandemic. Schools that participated in ICILS 2018 were asked to support the collection of data from the same individual teachers that participated in ICILS 2018. In addition, the currently serving principals and ICT coordinators from those schools were invited to complete questionnaires to collect school-level information. The international report first describes the responses to the COVID-19-reated educational disruption in the participating countries at national level, followed by the analyses on changes in the use of ICT between 2018 and 2020, and changes in social inequality of educational opportunity. The report also provides a comprehensive account of the conceptual, methodological, and analytical implementation of the study. It details information on the methods and procedures including instruments and data collection, sample, computation of weights, and variance estimation. The results of the ICILS Teacher Panel will support policymakers and education systems to develop a better understanding of the effective use of information and communication technology in education to better support ICT-based remote teaching and learning.