This chapter discusses the on line and electronically delivered questionnaires that have become an increasingly useful option for international large‐scale sample surveys and assessments. TALIS offered on line data collection (ODC) with a mixed‐mode design as an international option: countries could use the option as a default means to collect data for all schools and respondents, selected schools only or a particular population, i.e. school principals or teachers. This chapter provides information on the design, operations, technical solutions, field trial, main study and on line data collection processes.