In survey research, cognitive pretesting is generally considered an essential prerequisite for the successful development of a questionnaire and thus for the quality of the data collected within the framework of a survey. This contribution provides an introduction to the topic of questionnaire pretesting and focuses especially on the planning and implementation of cognitive pretests. The following questions are addressed, in particular: What is a pretest and why should you conduct questionnaire pretests? What pretesting procedures are available and which one should you choose? What techniques are applied in cognitive pretests? How are cognitive pretests conducted? How are cognitive pretests evaluated?